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  Network Working Group                                      J. Oikarinen

  Request for Comments: 1459                                      D. Reed

                                                                 May 1993

                        Internet Relay Chat Protocol

  Status of This Memo

  This memo defines an Experimental Protocol for the Internet community.
  Discussion and suggestions for improvement are requested. Please refer
  to the current edition of the "IAB Official Protocol Standards" for the
  standardization state and status of this protocol. Distribution of this
  memo is unlimited.

  Abstract

  The IRC protocol was developed over the last 4 years since it was first
  implemented as a means for users on a BBS to chat amongst themselves.
  Now it supports a world-wide network of servers and clients, and is
  stringing to cope with growth. Over the past 2 years, the average number
  of users connected to the main IRC network has grown by a factor of 10.

  The IRC protocol is a text-based protocol, with the simplest client
  being any socket program capable of connecting to the server.

  Table of Contents

        INTRODUCTION  ...............................................    4

        1.1  Servers ................................................    4

        1.2  Clients ................................................    5

           1.2.1 Operators ..........................................    5

        1.3 Channels ................................................    5

        1.3.1  Channel Operators ....................................    6

        THE IRC SPECIFICATION .......................................    7

        2.1 Overview ................................................    7

        2.2 Character codes .........................................    7

        2.3 Messages ................................................    7

           2.3.1  Message format in 'pseudo' BNF ....................    8

        2.4 Numeric replies .........................................   10

        IRC Concepts ................................................   10

        3.1 One-to-one communication ................................   10

        3.2 One-to-many .............................................   11

           3.2.1 To a list ..........................................   11

           3.2.2 To a group (channel) ...............................   11

           3.2.3 To a host/server mask ..............................   12

        3.3 One to all ..............................................   12

           3.3.1 Client to Client ...................................   12

           3.3.2 Clients to Server ..................................   12

           3.3.3 Server to Server ...................................   12

     4. MESSAGE DETAILS .............................................   13

        4.1 Connection Registration .................................   13

           4.1.1 Password message ...................................   14

           4.1.2 Nickname message ...................................   14

           4.1.3 User message .......................................   15

           4.1.4 Server message .....................................   16

           4.1.5 Operator message ...................................   17

           4.1.6 Quit message .......................................   17

           4.1.7 Server Quit message ................................   18

        4.2 Channel operations ......................................   19

           4.2.1 Join message .......................................   19

           4.2.2 Part message .......................................   20

           4.2.3 Mode message .......................................   21

              4.2.3.1 Channel modes .................................   21

              4.2.3.2 User modes ....................................   22

           4.2.4 Topic message ......................................   23

           4.2.5 Names message ......................................   24

           4.2.6 List message .......................................   24

           4.2.7 Invite message .....................................   25

           4.2.8 Kick message .......................................   25

        4.3 Server queries and commands .............................   26

           4.3.1 Version message ....................................   26

           4.3.2 Stats message ......................................   27

           4.3.3 Links message ......................................   28

           4.3.4 Time message .......................................   29

           4.3.5 Connect message ....................................   29

           4.3.6 Trace message ......................................   30

           4.3.7 Admin message ......................................   31

           4.3.8 Info message .......................................   31

        4.4 Sending messages ........................................   32

           4.4.1 Private messages ...................................   32

           4.4.2 Notice messages ....................................   33

        4.5 User-based queries ......................................   33

           4.5.1 Who query ..........................................   33

           4.5.2 Whois query ........................................   34

           4.5.3 Whowas message .....................................   35

        4.6 Miscellaneous messages ..................................   35

           4.6.1 Kill message .......................................   36

           4.6.2 Ping message .......................................   37

           4.6.3 Pong message .......................................   37

           4.6.4 Error message ......................................   38

     5. OPTIONAL MESSAGES ...........................................   38

        5.1 Away message ............................................   38

        5.2 Rehash command ..........................................   39

        5.3 Restart command .........................................   39

        5.4 Summon message ..........................................   40

        5.5 Users message ...........................................   40

        5.6 Operwall command ........................................   41

        5.7 Userhost message ........................................   42

        5.8 Ison message ............................................   42

     6. REPLIES .....................................................   43

        6.1 Error Replies ...........................................   43

        6.2 Command responses .......................................   48

        6.3 Reserved numerics .......................................   56

     7. Client and server authentication ............................   56

     8. Current Implementations Details .............................   56

        8.1 Network protocol: TCP ...................................   57

           8.1.1 Support of Unix sockets ............................   57

        8.2 Command Parsing .........................................   57

        8.3 Message delivery ........................................   57

        8.4 Connection 'Liveness' ...................................   58

        8.5 Establishing a server-client connection .................   58

        8.6 Establishing a server-server connection .................   58

           8.6.1 State information exchange when connecting .........   59

        8.7 Terminating server-client connections ...................   59

        8.8 Terminating server-server connections ...................   59

        8.9 Tracking nickname changes ...............................   60

        8.10 Flood control of clients ...............................   60

        8.11 Non-blocking lookups ...................................   61

           8.11.1 Hostname (DNS) lookups ............................   61

           8.11.2 Username (Ident) lookups ..........................   61

        8.12 Configuration file .....................................   61

           8.12.1 Allowing clients to connect .......................   62

           8.12.2 Operators .........................................   62

           8.12.3 Allowing servers to connect .......................   62

           8.12.4 Administrivia .....................................   63

        8.13 Channel membership .....................................   63

     9. Current problems ............................................   63

        9.1 Scalability .............................................   63

        9.2 Labels ..................................................   63

           9.2.1 Nicknames ..........................................   63

           9.2.2 Channels ...........................................   64

           9.2.3 Servers ............................................   64

        9.3 Algorithms ..............................................   64

     10. Support and availability ...................................   64

     11. Security Considerations ....................................   65

     12. Authors' Addresses .........................................   65

 INTRODUCTION

 The IRC (Internet Relay Chat) protocol has been designed over a number of
 years for use with text based conferencing. This document describes the
 current IRC protocol.

 The IRC protocol has been developed on systems using the TCP/IP network
 protocol, although there is no requirement that this remain the only
 sphere in which it operates.

 IRC itself is a teleconferencing system, which (through the use of the
 client-server model) is well-suited to running on many machines in a
 distributed fashion. A typical setup involves a single process (the
 server) forming a central point for clients (or other servers) to connect
 to, performing the required message delivery/multiplexing and other
 functions.

 1.1 Servers

 The server forms the backbone of IRC, providing a point to which clients
 may connect to to talk to each other, and a point for other servers to
 connect to, forming an IRC network. The only network configuration allowed
 for IRC servers is that of a spanning tree [see Fig. 1] where each server
 acts as a central node for the rest of the net it sees.

                            [ Server 15 ]  [ Server 13 ] [ Server 14]

                                  /                \         /

                                 /                  \       /

         [ Server 11 ] ------ [ Server 1 ]       [ Server 12]

                               /        \          /

                              /          \        /

                   [ Server 2 ]          [ Server 3 ]

                     /       \                      \

                    /         \                      \

            [ Server 4 ]    [ Server 5 ]         [ Server 6 ]

             /    |    \                           /

            /     |     \                         /

           /      |      \____                   /

          /       |           \                 /

  [ Server 7 ] [ Server 8 ] [ Server 9 ]   [ Server 10 ]

                                   :

                                [ etc. ]

                                   :

                  [ Fig. 1. Format of IRC server network ]

 1.2 Clients

 A client is anything connecting to a server that is not another server.
 Each client is distinguished from other clients by a unique nickname
 having a maximum length of nine (9) characters. See the protocol grammar
 rules for what may and may not be used in a nickname. In addition to the
 nickname, all servers must have the following information about all
 clients: the real name of the host that the client is running on, the
 username of the client on that host, and the server to which the client is
 connected.

 1.2.1 Operators

 To allow a reasonable amount of order to be kept within the IRC network, a
 special class of clients (operators) is allowed to perform general
 maintenance functions on the network. Although the powers granted to an
 operator can be considered as 'dangerous', they are nonetheless required.
 Operators should be able to perform basic network tasks such as
 disconnecting and reconnecting servers as needed to prevent long-term use
 of bad network routing. In recognition of this need, the protocol
 discussed herein provides for operators only to be able to perform such
 functions. See sections 4.1.7 (SQUIT) and 4.3.5 (CONNECT).

 A more controversial power of operators is the ability to remove a user
 from the connected network by 'force', i.e. operators are able to close
 the connection between any client and server. The justification for this
 is delicate since its abuse is both destructive and annoying. For further
 details on this type of action, see section 4.6.1 (KILL).

 1.3 Channels

 A channel is a named group of one or more clients which will all receive
 messages addressed to that channel. The channel is created implicitly when
 the first client joins it, and the channel ceases to exist when the last
 client leaves it. While channel exists, any client can reference the
 channel using the name of the channel.

 Channels names are strings (beginning with a '&' or '#' character) of
 length up to 200 characters. Apart from the the requirement that the first
 character being either '&' or '#'; the only restriction on a channel name
 is that it may not contain any spaces (' '), a control G (^G or ASCII 7),
 or a comma (',' which is used as a list item separator by the protocol).

 There are two types of channels allowed by this protocol. One is a
 distributed channel which is known to all the servers that are connected
 to the network. These channels are marked by the first character being a
 only clients on the server where it exists may join it. These are
 distinguished by a leading '&' character. On top of these two types, there
 are the various channel modes available to alter the characteristics of
 individual channels. See section 4.2.3 (MODE command) for more details on
 this.

 To create a new channel or become part of an existing channel, a user is
 required to JOIN the channel. If the channel doesn't exist prior to
 joining, the channel is created and the creating user becomes a channel
 operator. If the channel already exists, whether or not your request to
 JOIN that channel is honoured depends on the current modes of the channel.
 For example, if the channel is invite-only, (+i), then you may only join
 if invited. As part of the protocol, a user may be a part of several
 channels at once, but a limit of ten (10) channels is recommended as being
 ample for both experienced and novice users. See section 8.13 for more
 information on this.

 If the IRC network becomes disjoint because of a split between two
 servers, the channel on each side is only composed of those clients which
 are connected to servers on the respective sides of the split, possibly
 ceasing to exist on one side of the split. When the split is healed, the
 connecting servers announce to each other who they think is in each
 channel and the mode of that channel. If the channel exists on both sides,
 the JOINs and MODEs are interpreted in an inclusive manner so that both
 sides of the new connection will agree about which clients are in the
 channel and what modes the channel has.

 1.3.1 Channel Operators

 The channel operator (also referred to as a "chop" or "chanop") on a given
 channel is considered to 'own' that channel. In recognition of this
 status, channel operators are endowed with certain powers which enable
 them to keep control and some sort of sanity in their channel. As an owner
 of a channel, a channel operator is not required to have reasons for their
 actions, although if their actions are generally antisocial or otherwise
 abusive, it might be reasonable to ask an IRC operator to intervene, or
 for the usersjust leave and go elsewhere and form their own channel.

 The commands which may only be used by channel operators are:

         KICK    - Eject a client from the channel

         MODE    - Change the channel's mode

         INVITE  - Invite a client to an invite-only channel (mode +i)

         TOPIC   - Change the channel topic in a mode +t channel

 A channel operator is identified by the '@' symbol next to their nickname
 whenever it is associated with a channel (ie replies to the NAMES, WHO and
 WHOIS commands).

 2. The IRC Specification

 2.1 Overview

 The protocol as described herein is for use both with server to server and
 client to server connections. There are, however, more restrictions on
 client connections (which are considered to be untrustworthy) than on
 server connections.

 2.2 Character codes

 No specific character set is specified. The protocol is based on a a set
 of codes which are composed of eight (8) bits, making up an octet. Each
 message may be composed of any number of these octets; however, some octet
 values are used for control codes which act as message delimiters.

 Regardless of being an 8-bit protocol, the delimiters and keywords are
 such that protocol is mostly usable from USASCII terminal and a telnet
 connection.

 Because of IRC's scandanavian origin, the characters {}| are considered to
 be the lower case equivalents of the characters []\, respectively. This is
 a critical issue when determining the equivalence of two nicknames.

 2.3 Messages

 Servers and clients send eachother messages which may or may not generate
 a reply. If the message contains a valid command, as described in later
 sections, the client should expect a reply as specified but it is not
 advised to wait forever for the reply; client to server and server to
 server communication is essentially asynchronous in nature.

 Each IRC message may consist of up to three main parts: the prefix
 (optional), the command, and the command parameters (of which there may be
 up to 15). The prefix, command, and all parameters are separated by one
 (or more) ASCII space character(s) (0x20).

 The presence of a prefix is indicated with a single leading ASCII colon
 character (':', 0x3b), which must be the first character of the message
 itself. There must be no gap (whitespace) between the colon and the
 prefix. The prefix is used by servers to indicate the true origin of the
 message. If the prefix is missing from the message, it is assumed to have
 originated from the connection from which it was received. Clients should
 not use prefix when sending a message from themselves; if they use a
 prefix, the only valid prefix is the registered nickname associated with
 the client. If the source identified by the prefix cannot be found from
 the server's internal database, or if the source is registered from a
 different link than from which the message arrived, the server must ignore
 the message silently.

 The command must either be a valid IRC command or a three (3) digit number
 represented in ASCII text.

 IRC messages are always lines of characters terminated with a CR-LF
 (Carriage Return - Line Feed) pair, and these messages shall not exceed
 512 characters in length, counting all characters including the trailing
 CR-LF. Thus, there are 510 characters maximum allowed for the command and
 its parameters. There is no provision for continuation message lines. See
 section 7 for more details about current implementations.

 2.3.1 Message format in 'pseudo' BNF

 The protocol messages must be extracted from the contiguous stream of
 octets. The current solution is to designate two characters, CR and LF, as
 message separators. Empty messages are silently ignored, which permits use
 of the sequence CR-LF between messages without extra problems.

 The extracted message is parsed into the components <prefix>, <command>
 and list of parameters matched either by <middle> or <trailing>
 components.

 The BNF representation for this is:

 <message>  ::= [':' <prefix> <SPACE> ] <command> <params> <crlf>

 <prefix>   ::= <servername> | <nick> [ '!' <user> ] [ '@' <host> ]

 <command>  ::= <letter> { <letter> } | <number> <number> <number>

 <SPACE>    ::= ' ' { ' ' }

 <params>   ::= <SPACE> [ ':' <trailing> | <middle> <params> ]

 <middle>   ::= <Any *non-empty* sequence of octets not including SPACE

                  or NUL or CR or LF, the first of which may not be ':'>

 <trailing> ::= <Any, possibly *empty*, sequence of octets not including

                  NUL or CR or LF>

 <crlf>     ::= CR LF

 NOTES:

   1. <SPACE> is consists only of SPACE character(s) (0x20). Specially
      notice that TABULATION, and all other control characters are
      considered NON-WHITE-SPACE.
   2. After extracting the parameter list, all parameters are equal,
      whether matched by <middle> or <trailing>. <Trailing> is just a
      syntactic trick to allow SPACE within parameter.
   3. The fact that CR and LF cannot appear in parameter strings is just
      artifact of the message framing. This might change later.
   4. The NUL character is not special in message framing, and basically
      could end up inside a parameter, but as it would cause extra
      complexities in normal C string handling. Therefore NUL is not
      allowed within messages.
   5. The last parameter may be an empty string.
   6. Use of the extended prefix (['!' <user> ] ['@' <host> ]) must not be
      used in server to server communications and is only intended for
      server to client messages in order to provide clients with more
      useful information about who a message is from without the need for
      additional queries.

 Most protocol messages specify additional semantics and syntax for the
 extracted parameter strings dictated by their position in the list. For
 example, many server commands will assume that the first parameter after
 the command is the list of targets, which can be described with:

    <target>     ::= <to> [ "," <target> ]

    <to>         ::= <channel> | <user> '@' <servername> | <nick> | <mask>

    <channel>    ::= ('#' | '&') <chstring>

    <servername> ::= <host>

    <host>       ::= see RFC 952 [DNS:4] for details on allowed hostnames

    <nick>       ::= <letter> { <letter> | <number> | <special> }

    <mask>       ::= ('#' | '$') <chstring>

    <chstring>   ::= <any 8bit code except SPACE, BELL, NUL, CR, LF and

                      comma (',')>

 Other parameter syntaxes are:

    <user>       ::= <nonwhite> { <nonwhite> }

    <letter>     ::= 'a' ... 'z' | 'A' ... 'Z'

    <number>     ::= '0' ... '9'

    <special>    ::= '-' | '[' | ']' | '\' | '`' | '^' | '{' | '}'

    <nonwhite>   ::= <any 8bit code except SPACE (0x20), NUL (0x0), CR

                      (0xd), and LF (0xa)>

 2.4 Numeric replies

 Most of the messages sent to the server generate a reply of some sort. The
 most common reply is the numeric reply, used for both errors and normal
 replies. The numeric reply must be sent as one message consisting of the
 sender prefix, the three digit numeric, and the target of the reply. A
 numeric reply is not allowed to originate from a client; any such messages
 received by a server are silently dropped. In all other respects, a
 numeric reply is just like a normal message, except that the keyword is
 made up of 3 numeric digits rather than a string of letters. A list of
 different replies is supplied in section 6.

 3. IRC Concepts.

 This section is devoted to describing the actual concepts behind the
 organization of the IRC protocol and how the current implementations
 deliver different classes of messages.

                           1--\

                               A        D---4

                           2--/ \      /

                                 B----C

                                /      \

                               3        E

    Servers: A, B, C, D, E         Clients: 1, 2, 3, 4

                     [ Fig. 2. Sample small IRC network ]

 3.1 One-to-one communication

 Communication on a one-to-one basis is usually only performed by clients,
 since most server-server traffic is not a result of servers talking only
 to each other. To provide a secure means for clients to talk to each
 other, it is required that all servers be able to send a message in
 exactly one direction along the spanning tree in order to reach any
 client. The path of a message being delivered is the shortest path between
 any two points on the spanning tree.

 The following examples all refer to Figure 2 above.

 Example 1:

        A message between clients 1 and 2 is only seen by server A, which

        sends it straight to client 2.

 Example 2:

        A message between clients 1 and 3 is seen by servers A & B, and

        client 3.  No other clients or servers are allowed see the message.

 Example 3:

        A message between clients 2 and 4 is seen by servers A, B, C & D

        and client 4 only.

 3.2 One-to-many

 The main goal of IRC is to provide a forum which allows easy and efficient
 conferencing (one to many conversations). IRC offers several means to
 achieve this, each serving its own purpose.

 3.2.1 To a list

 The least efficient style of one-to-many conversation is through clients
 talking to a 'list' of users. How this is done is almost self explanatory:
 the client gives a list of destinations to which the message is to be
 delivered and the server breaks it up and dispatches a separate copy of
 the message to each given destination. This isn't as efficient as using a
 group since the destination list is broken up and the dispatch sent
 without checking to make sure duplicates aren't sent down each path.

 3.2.2 To a group (channel)

 In IRC the channel has a role equivalent to that of the multicast group;
 their existence is dynamic (coming and going as people join and leave
 channels) and the actual conversation carried out on a channel is only
 sent to servers which are supporting users on a given channel. If there
 are multiple users on a server in the same channel, the message text is
 sent only once to that server and then sent to each client on the channel.
 This action is then repeated for each client-server combination until the
 original message has fanned out and reached each member of the channel.

 The following examples all refer to Figure 2.

 Example 4:

        Any channel with 1 client in it. Messages to the channel go to the

        server and then nowhere else.

 Example 5:

        2 clients in a channel. All messages traverse a path as if they

        were private messages between the two clients outside a channel.

 Example 6:

        Clients 1, 2 and 3 in a channel.  All messages to the channel are

        sent to all clients and only those servers which must be traversed

        by the message if it were a private message to a single client.  If

        client 1 sends a message, it goes back to client 2 and then via

        server B to client 3.

 3.2.3 To a host/server mask

 To provide IRC operators with some mechanism to send messages to a large
 body of related users, host and server mask messages are provided. These
 messages are sent to users whose host or server information match that of
 the mask. The messages are only sent to locations where users are, in a
 fashion similar to that of channels.

 3.3 One-to-all

 The one-to-all type of message is better described as a broadcast message,
 sent to all clients or servers or both. On a large network of users and
 servers, a single message can result in a lot of traffic being sent over
 the network in an effort to reach all of the desired destinations.

 For some messages, there is no option but to broadcast it to all servers
 so that the state information held by each server is reasonably consistent
 between servers.

 3.3.1 Client-to-Client

 There is no class of message which, from a single message, results in a
 message being sent to every other client.

 3.3.2 Client-to-Server

 Most of the commands which result in a change of state information (such
 as channel membership, channel mode, user status, etc) must be sent to all
 servers by default, and this distribution may not be changed by the
 client.

 3.3.3 Server-to-Server.

 While most messages between servers are distributed to all 'other'
 servers, this is only required for any message that affects either a user,
 channel or server. Since these are the basic items found in

 IRC, nearly all messages originating from a server are broadcast to all
 other connected servers.

 4. Message details

 On the following pages are descriptions of each message recognized by the
 IRC server and client. All commands described in this section must be
 implemented by any server for this protocol.

 Where the reply ERR_NOSUCHSERVER is listed, it means that the <server>
 parameter could not be found. The server must not send any other replies
 after this for that command.

 The server to which a client is connected is required to parse the
 complete message, returning any appropriate errors. If the server
 encounters a fatal error while parsing a message, an error must be sent
 back to the client and the parsing terminated. A fatal error may be
 considered to be incorrect command, a destination which is otherwise
 unknown to the server (server, nick or channel names fit this category),
 not enough parameters or incorrect privileges.

 If a full set of parameters is presented, then each must be checked for
 validity and appropriate responses sent back to the client. In the case of
 messages which use parameter lists using the comma as an item separator, a
 reply must be sent for each item.

 In the examples below, some messages appear using the full format:

 :Name COMMAND parameter list

 Such examples represent a message from "Name" in transit between servers,
 where it is essential to include the name of the original sender of the
 message so remote servers may send back a reply along the correct path.

 4.1 Connection Registration

 The commands described here are used to register a connection with an IRC
 server as either a user or a server as well as correctly disconnect.

 A "PASS" command is not required for either client or server connection to
 be registered, but it must precede the server message or the latter of the
 NICK/USER combination. It is strongly recommended that all server
 connections have a password in order to give some level of security to the
 actual connections. The recommended order for a client to register is as
 follows:

   1. Pass message
   2. Nick message
   3. User message

 4.1.1 Password message

 Command: PASS
 Parameters: <password>

 The PASS command is used to set a 'connection password'. The password can
 and must be set before any attempt to register the connection is made.
 Currently this requires that clients send a PASS command before sending
 the NICK/USER combination and servers *must* send a PASS command before
 any SERVER command. The password supplied must match the one contained in
 the C/N lines (for servers) or I lines (for clients). It is possible to
 send multiple PASS commands before registering but only the last one sent
 is used for verification and it may not be changed once registered.
 Numeric Replies:

 ERR_NEEDMOREPARAMS ERR_ALREADYREGISTRED

 Example:

 PASS secretpasswordhere

 4.1.2 Nick message

 Command: NICK
 Parameters: <nickname> [ <hopcount> ]

 NICK message is used to give user a nickname or change the previous one.
 The <hopcount> parameter is only used by servers to indicate how far away
 a nick is from its home server. A local connection has a hopcount of 0. If
 supplied by a client, it must be ignored.

 If a NICK message arrives at a server which already knows about an
 identical nickname for another client, a nickname collision occurs. As a
 result of a nickname collision, all instances of the nickname are removed
 from the server's database, and a KILL command is issued to remove the
 nickname from all other server's database. If the NICK message causing the
 collision was a nickname change, then the original (old) nick must be
 removed as well.

 If the server recieves an identical NICK from a client which is directly
 connected, it may issue an ERR_NICKCOLLISION to the local client, drop the
 NICK command, and not generate any kills.

 Numeric Replies:

            ERR_NONICKNAMEGIVEN             ERR_ERRONEUSNICKNAME

            ERR_NICKNAMEINUSE               ERR_NICKCOLLISION

 Example:

 NICK Wiz ; Introducing new nick "Wiz".

 :WiZ NICK Kilroy ; WiZ changed his nickname to Kilroy.

 4.1.3 User message

 Command: USER
 Parameters: <username> <hostname> <servername> <realname>

 The USER message is used at the beginning of connection to specify the
 username, hostname, servername and realname of s new user. It is also used
 in communication between servers to indicate new user arriving on IRC,
 since only after both USER and NICK have been received from a client does
 a user become registered.

 Between servers USER must to be prefixed with client's NICKname. Note that
 hostname and servername are normally ignored by the IRC server when the
 USER command comes from a directly connected client (for security
 reasons), but they are used in server to server communication. This means
 that a NICK must always be sent to a remote server when a new user is
 being introduced to the rest of the network before the accompanying USER
 is sent.

 It must be noted that realname parameter must be the last parameter,
 because it may contain space characters and must be prefixed with a colon
 (':') to make sure this is recognised as such.

 Since it is easy for a client to lie about its username by relying solely
 on the USER message, the use of an "Identity Server" is recommended. If
 the host which a user connects from has such a server enabled the username
 is set to that as in the reply from the "Identity Server".

 Numeric Replies:

 ERR_NEEDMOREPARAMS ERR_ALREADYREGISTRED

 Examples:

 USER guest tolmoon tolsun :Ronnie Reagan

                                    ; User registering themselves with a

                                    username of "guest" and real name

                                    "Ronnie Reagan".

    :testnick USER guest tolmoon tolsun :Ronnie Reagan

                                    ; message between servers with the

                                    nickname for which the USER command

                                    belongs to

 4.1.4 Server message

 Command: SERVER
 Parameters: <servername> <hopcount> <info>

 The server message is used to tell a server that the other end of a new
 connection is a server. This message is also used to pass server data over
 whole net. When a new server is connected to net, information about it be
 broadcast to the whole network. <hopcount> is used to give all servers
 some internal information on how far away all servers are. With a full
 server list, it would be possible to construct a map of the entire server
 tree, but hostmasks prevent this from being done.

 The SERVER message must only be accepted from either (a) a connection
 which is yet to be registered and is attempting to register as a server,
 or (b) an existing connection to another server, in which case the SERVER
 message is introducing a new server behind that server.

 Most errors that occur with the receipt of a SERVER command result in the
 connection being terminated by the destination host (target SERVER). Error
 replies are usually sent using the "ERROR" command rather than the numeric
 since the ERROR command has several useful properties which make it useful
 here.

 If a SERVER message is parsed and attempts to introduce a server which is
 already known to the receiving server, the connection from which that
 message must be closed (following the correct procedures), since a
 duplicate route to a server has formed and the acyclic nature of the IRC
 tree broken.

 Numeric Replies:

 ERR_ALREADYREGISTRED

 Example:

 SERVER test.oulu.fi 1 :[tolsun.oulu.fi] Experimental server

                                 ; New server test.oulu.fi introducing

                                 itself and attempting to register.  The

                                 name in []'s is the hostname for the

                                 host running test.oulu.fi.

 :tolsun.oulu.fi SERVER csd.bu.edu 5 :BU Central Server

                                 ; Server tolsun.oulu.fi is our uplink

                                 for csd.bu.edu which is 5 hops away.

 4.1.5 Oper

 Command: OPER
 Parameters: <user> <password>

 OPER message is used by a normal user to obtain operator privileges. The
 combination of <user> and <password> are required to gain Operator
 privileges.

 If the client sending the OPER command supplies the correct password for
 the given user, the server then informs the rest of the network of the new
 operator by issuing a "MODE +o" for the clients nickname.

 The OPER message is client-server only.

 Numeric Replies:

            ERR_NEEDMOREPARAMS              RPL_YOUREOPER

            ERR_NOOPERHOST                  ERR_PASSWDMISMATCH

 Example:

    OPER foo bar                    ; Attempt to register as an operator

                                    using a username of "foo" and "bar" as

                                    the password.

 4.1.6 Quit

 Command: QUIT
 Parameters: [<Quit message>]

 A client session is ended with a quit message. The server must close the
 connection to a client which sends a QUIT message. If a "Quit Message" is
 given, this will be sent instead of the default message, the nickname.

 When netsplits (disconnecting of two servers) occur, the quit message is
 composed of the names of two servers involved, separated by a space. The
 first name is that of the server which is still connected and the second
 name is that of the server that has become disconnected.

 If, for some other reason, a client connection is closed without the
 client issuing a QUIT command (e.g. client dies and EOF occurs on socket),
 the server is required to fill in the quit message with some sort of
 message reflecting the nature of the event which caused it to happen.

 Numeric Replies:

 None.

 Examples:

 QUIT :Gone to have lunch ; Preferred message format.

 4.1.7 Server quit message

 Command: SQUIT
 Parameters: <server> <comment>

 The SQUIT message is needed to tell about quitting or dead servers. If a
 server wishes to break the connection to another server it must send a
 SQUIT message to the other server, using the the name of the other server
 as the server parameter, which then closes its connection to the quitting
 server.

 This command is also available operators to help keep a network of IRC
 servers connected in an orderly fashion. Operators may also issue an SQUIT
 message for a remote server connection. In this case, the SQUIT must be
 parsed by each server inbetween the operator and the remote server,
 updating the view of the network held by each server as explained below.

 The <comment> should be supplied by all operators who execute a SQUIT for
 a remote server (that is not connected to the server they are currently
 on) so that other operators are aware for the reason of this action. The
 <comment> is also filled in by servers which may place an error or similar
 message here.

 Both of the servers which are on either side of the connection being
 closed are required to to send out a SQUIT message (to all its other
 server connections) for all other servers which are considered to be
 behind that link.

 Similarly, a QUIT message must be sent to the other connected servers rest
 of the network on behalf of all clients behind that link. In addition to
 this, all channel members of a channel which lost a member due to the
 split must be sent a QUIT message.

 If a server connection is terminated prematurely (e.g. the server on the
 other end of the link died), the server which detects this disconnection
 is required to inform the rest of the network that the connection has
 closed and fill in the comment field with something appropriate.

 Numeric replies:

 ERR_NOPRIVILEGES ERR_NOSUCHSERVER

 Example:

 SQUIT tolsun.oulu.fi :Bad Link ? ; the server link tolson.oulu.fi has

 been terminated because of "Bad Link".

 :Trillian SQUIT cm22.eng.umd.edu :Server out of control

                                     ; message from Trillian to disconnect

                                    "cm22.eng.umd.edu" from the net

                                     because "Server out of control".

 4.2 Channel operations

 This group of messages is concerned with manipulating channels, their
 properties (channel modes), and their contents (typically clients). In
 implementing these, a number of race conditions are inevitable when
 clients at opposing ends of a network send commands which will ultimately
 clash. It is also required that servers keep a nickname history to ensure
 that wherever a <nick> parameter is given, the server check its history in
 case it has recently been changed.

 4.2.1 Join message

 Command: JOIN
 Parameters: <channel>{,<channel>} [<key>{,<key>}]

 The JOIN command is used by client to start listening a specific channel.
 Whether or not a client is allowed to join a channel is checked only by
 the server the client is connected to; all other servers automatically add
 the user to the channel when it is received from other servers. The
 conditions which affect this are as follows:

            1.  the user must be invited if the channel is invite-only;

            2.  the user's nick/username/hostname must not match any

                active bans;

            3.  the correct key (password) must be given if it is set.

 These are discussed in more detail under the MODE command (see section
 4.2.3 for more details).

 Once a user has joined a channel, they receive notice about all commands
 their server receives which affect the channel. This includes MODE, KICK,
 PART, QUIT and of course PRIVMSG/NOTICE. The JOIN command needs to be
 broadcast to all servers so that each server knows where to find the users
 who are on the channel. This allows optimal delivery of PRIVMSG/NOTICE
 messages to the channel.

 If a JOIN is successful, the user is then sent the channel's topic (using
 RPL_TOPIC) and the list of users who are on the channel (using
 RPL_NAMREPLY), which must include the user joining.

 Numeric Replies:

            ERR_NEEDMOREPARAMS              ERR_BANNEDFROMCHAN

            ERR_INVITEONLYCHAN              ERR_BADCHANNELKEY

            ERR_CHANNELISFULL               ERR_BADCHANMASK

            ERR_NOSUCHCHANNEL               ERR_TOOMANYCHANNELS

            RPL_TOPIC

 Examples:

    JOIN #foobar                    ; join channel #foobar.

    JOIN &foo fubar                 ; join channel &foo using key "fubar".

    JOIN #foo,&bar fubar            ; join channel #foo using key "fubar"

                                    and &bar using no key.

    JOIN #foo,#bar fubar,foobar     ; join channel #foo using key "fubar".

                                    and channel #bar using key "foobar".

    JOIN #foo,#bar                  ; join channels #foo and #bar.

    :WiZ JOIN #Twilight_zone        ; JOIN message from WiZ

 4.2.2 Part message

 Command: PART
 Parameters: <channel>{,<channel>}

 The PART message causes the client sending the message to be removed from
 the list of active users for all given channels listed in the parameter
 string.

 Numeric Replies:

            ERR_NEEDMOREPARAMS              ERR_NOSUCHCHANNEL

            ERR_NOTONCHANNEL

 Examples:

    PART #twilight_zone             ; leave channel "#twilight_zone"

    PART #oz-ops,&group5            ; leave both channels "&group5" and

                                    "#oz-ops".

 4.2.3 Mode message

 Command: MODE

 The MODE command is a dual-purpose command in IRC. It allows both
 usernames and channels to have their mode changed. The rationale for this
 choice is that one day nicknames will be obsolete and the equivalent
 property will be the channel.

 When parsing MODE messages, it is recommended that the entire message be
 parsed first and then the changes which resulted then passed on.

 4.2.3.1 Channel modes

 Parameters: <channel> {[+|-]|o|p|s|i|t|n|b|v} [<limit>] [<user>]

 [<ban mask>]

 The MODE command is provided so that channel operators may change the
 characteristics of `their' channel. It is also required that servers be
 able to change channel modes so that channel operators may be created.

 The various modes available for channels are as follows:

            o - give/take channel operator privileges;

            p - private channel flag;

            s - secret channel flag;

            i - invite-only channel flag;

            t - topic settable by channel operator only flag;

            n - no messages to channel from clients on the outside;

            m - moderated channel;

            l - set the user limit to channel;

            b - set a ban mask to keep users out;

            v - give/take the ability to speak on a moderated channel;

            k - set a channel key (password).

 When using the 'o' and 'b' options, a restriction on a total of three per
 mode command has been imposed. That is, any combination of 'o' and

 4.2.3.2 User modes

 Parameters: <nickname> {[+|-]|i|w|s|o}

 The user MODEs are typically changes which affect either how the client is
 seen by others or what 'extra' messages the client is sent. A user MODE
 command may only be accepted if both the sender of the message and the
 nickname given as a parameter are both the same.

 The available modes are as follows:

            i - marks a users as invisible;

            s - marks a user for receipt of server notices;

            w - user receives wallops;

            o - operator flag.

 Additional modes may be available later on.

 If a user attempts to make themselves an operator using the "+o" flag, the
 attempt should be ignored. There is no restriction, however, on anyone
 `deopping' themselves (using "-o"). Numeric Replies:

            ERR_NEEDMOREPARAMS              RPL_CHANNELMODEIS

            ERR_CHANOPRIVSNEEDED            ERR_NOSUCHNICK

            ERR_NOTONCHANNEL                ERR_KEYSET

            RPL_BANLIST                     RPL_ENDOFBANLIST

            ERR_UNKNOWNMODE                 ERR_NOSUCHCHANNEL

            ERR_USERSDONTMATCH              RPL_UMODEIS

            ERR_UMODEUNKNOWNFLAG

 Examples:

 Use of Channel Modes:

 MODE #Finnish +im               ; Makes #Finnish channel moderated and

                                 'invite-only'.

 MODE #Finnish +o Kilroy         ; Gives 'chanop' privileges to Kilroy on

                                 channel #Finnish.

 MODE #Finnish +v Wiz            ; Allow WiZ to speak on #Finnish.

 MODE #Fins -s                   ; Removes 'secret' flag from channel

                                 #Fins.

 MODE #42 +k oulu                ; Set the channel key to "oulu".

 MODE #eu-opers +l 10            ; Set the limit for the number of users

                                 on channel to 10.

 MODE &oulu +b                   ; list ban masks set for channel.

 MODE &oulu +b *!*@*             ; prevent all users from joining.

 MODE &oulu +b *!*@*.edu         ; prevent any user from a hostname

                                 matching *.edu from joining.

         Use of user Modes:

 :MODE WiZ -w                    ; turns reception of WALLOPS messages

                                 off for WiZ.

 :Angel MODE Angel +i            ; Message from Angel to make themselves

                                 invisible.

 MODE WiZ -o                     ; WiZ 'deopping' (removing operator

                                 status).  The plain reverse of this

                                 command ("MODE WiZ +o") must not be

                                 allowed from users since would bypass

                                 the OPER command.

 4.2.4 Topic message

 Command: TOPIC
 Parameters: <channel> [<topic>]

 The TOPIC message is used to change or view the topic of a channel. The
 topic for channel <channel> is returned if there is no <topic> given. If
 the <topic> parameter is present, the topic for that channel will be
 changed, if the channel modes permit this action.

 Numeric Replies:

            ERR_NEEDMOREPARAMS              ERR_NOTONCHANNEL

            RPL_NOTOPIC                     RPL_TOPIC

            ERR_CHANOPRIVSNEEDED

 Examples:

 :Wiz TOPIC #test :New topic ;User Wiz setting the topic.

    TOPIC #test :another topic      ;set the topic on #test to "another

                                    topic".

    TOPIC #test                     ; check the topic for #test.

 4.2.5 Names message

 Command: NAMES
 Parameters: [<channel>{,<channel>}]

 By using the NAMES command, a user can list all nicknames that are visible
 to them on any channel that they can see. Channel names which they can see
 are those which aren't private (+p) or secret (+s) or those which they are
 actually on. The <channel> parameter specifies which channel(s) to return
 information about if valid. There is no error reply for bad channel names.

 If no <channel> parameter is given, a list of all channels and their
 occupants is returned. At the end of this list, a list of users who are
 visible but either not on any channel or not on a visible channel are
 listed as being on `channel' "*".

 Numerics:

 RPL_NAMREPLY RPL_ENDOFNAMES

 Examples:

    NAMES #twilight_zone,#42        ; list visible users on #twilight_zone

                                    and #42 if the channels are visible to

                                    you.

    NAMES                           ; list all visible channels and users

 4.2.6 List message

 Command: LIST
 Parameters: [<channel>{,<channel>} [<server>]]

 The list message is used to list channels and their topics. If the
 <channel> parameter is used, only the status of that channel is displayed.
 Private channels are listed (without their topics) as channel "Prv" unless
 the client generating the query is actually on that channel. Likewise,
 secret channels are not listed at all unless the client is a member of the
 channel in question.

 Numeric Replies:

            ERR_NOSUCHSERVER                RPL_LISTSTART

            RPL_LIST                        RPL_LISTEND

 Examples:

 LIST ; List all channels.

 LIST #twilight_zone,#42 ; List channels #twilight_zone and #42

 4.2.7 Invite message

 Command: INVITE
 Parameters: <nickname> <channel>

 The INVITE message is used to invite users to a channel. The parameter
 <nickname> is the nickname of the person to be invited to the target
 channel <channel>. There is no requirement that the channel the target
 user is being invited to must exist or be a valid channel. To invite a
 user to a channel which is invite only (MODE +i), the client sending the
 invite must be recognised as being a channel operator on the given
 channel.

 Numeric Replies:

            ERR_NEEDMOREPARAMS              ERR_NOSUCHNICK

            ERR_NOTONCHANNEL                ERR_USERONCHANNEL

            ERR_CHANOPRIVSNEEDED

            RPL_INVITING                    RPL_AWAY

 Examples:

    :Angel INVITE Wiz #Dust         ; User Angel inviting WiZ to channel

                                    #Dust

    INVITE Wiz #Twilight_Zone       ; Command to invite WiZ to

                                    #Twilight_zone

 4.2.8 Kick command

 Command: KICK
 Parameters: <channel> <user> [<comment>]

 The KICK command can be used to forcibly remove a user from a channel. It
 'kicks them out' of the channel (forced PART).

 Only a channel operator may kick another user out of a channel. Each
 server that receives a KICK message checks that it is valid (ie the sender
 is actually a channel operator) before removing the victim from the
 channel.

 Numeric Replies:

            ERR_NEEDMOREPARAMS              ERR_NOSUCHCHANNEL

            ERR_BADCHANMASK                 ERR_CHANOPRIVSNEEDED

            ERR_NOTONCHANNEL

 Examples:

 KICK &Melbourne Matthew ; Kick Matthew from &Melbourne

 KICK #Finnish John :Speaking English

                                 ; Kick John from #Finnish using

                                 "Speaking English" as the reason

                                 (comment).

 :WiZ KICK #Finnish John         ; KICK message from WiZ to remove John

                                 from channel #Finnish

 NOTE:

 It is possible to extend the KICK command parameters to the following:

 <channel>{,<channel>} <user>{,<user>} [<comment>]

 4.3 Server queries and commands

 The server query group of commands has been designed to return information
 about any server which is connected to the network. All servers connected
 must respond to these queries and respond correctly. Any invalid response
 (or lack thereof) must be considered a sign of a broken server and it must
 be disconnected/disabled as soon as possible until the situation is
 remedied.

 In these queries, where a parameter appears as "<server>", it will usually
 mean it can be a nickname or a server or a wildcard name of some sort. For
 each parameter, however, only one query and set of replies is to be
 generated.

 4.3.1 Version message

 Command: VERSION
 Parameters: [<server>]

 The VERSION message is used to query the version of the server program. An
 optional parameter <server> is used to query the version of the server
 program which a client is not directly connected to.

 Numeric Replies:

 ERR_NOSUCHSERVER RPL_VERSION

 Examples:

    :Wiz VERSION *.se               ; message from Wiz to check the version

                                    of a server matching "*.se"

    VERSION tolsun.oulu.fi          ; check the version of server

                                    "tolsun.oulu.fi".

 4.3.2 Stats message

 Command: STATS
 Parameters: [<query> [<server>]]

 The stats message is used to query statistics of certain server. If
 <server> parameter is omitted, only the end of stats reply is sent back.
 The implementation of this command is highly dependent on the server which
 replies, although the server must be able to supply information as
 described by the queries below (or similar).

 A query may be given by any single letter which is only checked by the
 destination server (if given as the <server> parameter) and is otherwise
 passed on by intermediate servers, ignored and unaltered. The following
 queries are those found in the current IRC implementation and provide a
 large portion of the setup information for that server. Although these may
 not be supported in the same way by other versions, all servers should be
 able to supply a valid reply to a STATS query which is consistent with the
 reply formats currently used and the purpose of the query.

 The currently supported queries are:

            c - returns a list of servers which the server may connect

                to or allow connections from;

            h - returns a list of servers which are either forced to be

                treated as leaves or allowed to act as hubs;

            i - returns a list of hosts which the server allows a client

                to connect from;

            k - returns a list of banned username/hostname combinations

                for that server;

            l - returns a list of the server's connections, showing how

                long each connection has been established and the traffic

                over that connection in bytes and messages for each

                direction;

            m - returns a list of commands supported by the server and

                the usage count for each if the usage count is non zero;

            o - returns a list of hosts from which normal clients may

                become operators;

            y - show Y (Class) lines from server's configuration file;

            u - returns a string showing how long the server has been up.

 Numeric Replies:

            ERR_NOSUCHSERVER

            RPL_STATSCLINE                  RPL_STATSNLINE

            RPL_STATSILINE                  RPL_STATSKLINE

            RPL_STATSQLINE                  RPL_STATSLLINE

            RPL_STATSLINKINFO               RPL_STATSUPTIME

            RPL_STATSCOMMANDS               RPL_STATSOLINE

            RPL_STATSHLINE                  RPL_ENDOFSTATS

 Examples:

 STATS m                         ; check the command usage for the server

                                 you are connected to

 :Wiz STATS c eff.org            ; request by WiZ for C/N line

                                 information from server eff.org

 4.3.3 Links message

 Command: LINKS
 Parameters: [[<remote server>] <server mask>]

 With LINKS, a user can list all servers which are known by the server
 answering the query. The returned list of servers must match the mask, or
 if no mask is given, the full list is returned.

 If <remote server> is given in addition to <server mask>, the LINKS
 command is forwarded to the first server found that matches that name (if
 any), and that server is then required to answer the query.

 Numeric Replies:

 ERR_NOSUCHSERVER

            RPL_LINKS                       RPL_ENDOFLINKS

 Examples:

 LINKS *.au                      ; list all servers which have a name

                                 that matches *.au;

 :WiZ LINKS *.bu.edu *.edu       ; LINKS message from WiZ to the first

                                 server matching *.edu for a list of

                                 servers matching *.bu.edu.

 4.3.4 Time message

 Command: TIME
 Parameters: [<server>]

 The time message is used to query local time from the specified server. If
 the server parameter is not given, the server handling the command must
 reply to the query.

 Numeric Replies:

 ERR_NOSUCHSERVER RPL_TIME

 Examples:

    TIME tolsun.oulu.fi             ; check the time on the server

                                    "tolson.oulu.fi"

    Angel TIME *.au                 ; user angel checking the time on a

                                    server matching "*.au"

 4.3.5 Connect message

 Command: CONNECT
 Parameters: <target server> [<port> [<remote server>]]

 The CONNECT command can be used to force a server to try to establish a
 new connection to another server immediately. CONNECT is a privileged
 command and is to be available only to IRC Operators. If a remote server
 is given then the CONNECT attempt is made by that server to <target
 server> and <port>.

 Numeric Replies:

            ERR_NOSUCHSERVER                ERR_NOPRIVILEGES

            ERR_NEEDMOREPARAMS

 Examples:

 CONNECT tolsun.oulu.fi          ; Attempt to connect a server to

                                 tolsun.oulu.fi

 :WiZ CONNECT eff.org 6667 csd.bu.edu

                                 ; CONNECT attempt by WiZ to get servers

                                 eff.org and csd.bu.edu connected on port

                                 6667.

 4.3.6 Trace message

 Command: TRACE
 Parameters: [<server>]

 TRACE command is used to find the route to specific server. Each server
 that processes this message must tell the sender about it by sending a
 reply indicating it is a pass-through link, forming a chain of replies
 similar to that gained from using "traceroute". After sending this reply
 back, it must then send the TRACE message to the next server until given
 server is reached. If the <server> parameter is omitted, it is recommended
 that TRACE command send a message to the sender telling which servers the
 current server has direct connection to.

 If the destination given by "<server>" is an actual server, then the
 destination server is required to report all servers and users which are
 connected to it, although only operators are permitted to see users
 present. If the destination given by <server> is a nickname, they only a
 reply for that nickname is given.

 Numeric Replies:

 ERR_NOSUCHSERVER

 If the TRACE message is destined for another server, all intermediate
 servers must return a RPL_TRACELINK reply to indicate that the TRACE
 passed through it and where its going next.

 RPL_TRACELINK
 A TRACE reply may be composed of any number of the following numeric
 replies.

            RPL_TRACECONNECTING             RPL_TRACEHANDSHAKE

            RPL_TRACEUNKNOWN                RPL_TRACEOPERATOR

            RPL_TRACEUSER                   RPL_TRACESERVER

            RPL_TRACESERVICE                RPL_TRACENEWTYPE

            RPL_TRACECLASS

 Examples:

 TRACE *.oulu.fi ; TRACE to a server matching *.oulu.fi

 :WiZ TRACE AngelDust ; TRACE issued by WiZ to nick AngelDust

 4.3.7 Admin command

 Command: ADMIN
 Parameters: [<server>]

 The admin message is used to find the name of the administrator of the
 given server, or current server if <server> parameter is omitted. Each
 server must have the ability to forward ADMIN messages to other servers.

 Numeric Replies:

            ERR_NOSUCHSERVER

            RPL_ADMINME                     RPL_ADMINLOC1

            RPL_ADMINLOC2                   RPL_ADMINEMAIL

 Examples:

    ADMIN tolsun.oulu.fi            ; request an ADMIN reply from

                                    tolsun.oulu.fi

    :WiZ ADMIN *.edu                ; ADMIN request from WiZ for first

                                    server found to match *.edu.

 4.3.8 Info command

 Command: INFO
 Parameters: [<server>]

 The INFO command is required to return information which describes the
 server: its version, when it was compiled, the patchlevel, when it was
 started, and any other miscellaneous information which may be considered
 to be relevant.

 Numeric Replies:

            ERR_NOSUCHSERVER

            RPL_INFO                        RPL_ENDOFINFO

 Examples:

 INFO csd.bu.edu ; request an INFO reply from csd.bu.edu

    :Avalon INFO *.fi               ; INFO request from Avalon for first

                                    server found to match *.fi.

    INFO Angel                      ; request info from the server that

                                    Angel is connected to.

 4.4 Sending messages

 The main purpose of the IRC protocol is to provide a base for clients to
 communicate with each other. PRIVMSG and NOTICE are the only messages
 available which actually perform delivery of a text message from one
 client to another - the rest just make it possible and try to ensure it
 happens in a reliable and structured manner.

 4.4.1 Private messages

 Command: PRIVMSG
 Parameters: <receiver>{,<receiver>} <text to be sent>

 PRIVMSG is used to send private messages between users. <receiver> is the
 nickname of the receiver of the message. <receiver> can also be a list of
 names or channels separated with commas.

 The <receiver> parameter may also me a host mask (#mask) or server mask
 ($mask). In both cases the server will only send the PRIVMSG to those who
 have a server or host matching the mask. The mask must have at least 1
 (one) "." in it and no wildcards following the last ".". This requirement
 exists to prevent people sending messages to "#*" or "$*", which would
 broadcast to all users; from experience, this is abused more than used
 responsibly and properly. Wildcards are the '*' and '?' characters. This
 extension to the PRIVMSG command is only available to Operators.

 Numeric Replies:

            ERR_NORECIPIENT                 ERR_NOTEXTTOSEND

            ERR_CANNOTSENDTOCHAN            ERR_NOTOPLEVEL

            ERR_WILDTOPLEVEL                ERR_TOOMANYTARGETS

            ERR_NOSUCHNICK

            RPL_AWAY

 Examples:

 :Angel PRIVMSG Wiz :Hello are you receiving this message ?

 ; Message from Angel to Wiz.

 PRIVMSG Angel :yes I'm receiving it !receiving it !'u>(768u+1n) .br ;

 Message to Angel.

 PRIVMSG jto@tolsun.oulu.fi :Hello !

 ; Message to a client on server

 tolsun.oulu.fi with username of "jto".

 PRIVMSG $*.fi :Server tolsun.oulu.fi rebooting.

                                 ; Message to everyone on a server which

                                 has a name matching *.fi.

 PRIVMSG #*.edu :NSFNet is undergoing work, expect interruptions

                                 ; Message to all users who come from a

                                 host which has a name matching *.edu.

 4.4.2 Notice

 Command: NOTICE
 Parameters: <nickname> <text>

 The NOTICE message is used similarly to PRIVMSG. The difference between
 NOTICE and PRIVMSG is that automatic replies must never be sent in
 response to a NOTICE message. This rule applies to servers too - they must
 not send any error reply back to the client on receipt of a notice. The
 object of this rule is to avoid loops between a client automatically
 sending something in response to something it received. This is typically
 used by automatons (clients with either an AI or other interactive program
 controlling their actions) which are always seen to be replying lest they
 end up in a loop with another automaton.

 See PRIVMSG for more details on replies and examples.

 4.5 User based queries

 User queries are a group of commands which are primarily concerned with
 finding details on a particular user or group users. When using wildcards
 with any of these commands, if they match, they will only return
 information on users who are 'visible' to you. The visibility of a user is
 determined as a combination of the user's mode and the common set of
 channels you are both on.

 4.5.1 Who query

 Command: WHO
 Parameters: [<name> [<o>]]

 The WHO message is used by a client to generate a query which returns a
 list of information which 'matches' the <name> parameter given by the
 client. In the absence of the <name> parameter, all visible (users who
 aren't invisible (user mode +i) and who don't have a common channel with
 the requesting client) are listed. The same result can be achieved by
 using a <name> of "0" or any wildcard which will end up matching every
 entry possible.

 The <name> passed to WHO is matched against users' host, server, real name
 and nickname if the channel <name> cannot be found.

 If the "o" parameter is passed only operators are returned according to
 the name mask supplied.

 Numeric Replies:

            ERR_NOSUCHSERVER

            RPL_WHOREPLY                    RPL_ENDOFWHO

 Examples:

    WHO *.fi                        ; List all users who match against

                                    "*.fi".

    WHO jto* o                      ; List all users with a match against

                                    "jto*" if they are an operator.

 4.5.2 Whois query

 Command: WHOIS
 Parameters: [<server>] <nickmask>[,<nickmask>[,...]]

 This message is used to query information about particular user. The
 server will answer this message with several numeric messages indicating
 different statuses of each user which matches the nickmask (if you are
 entitled to see them). If no wildcard is present in the <nickmask>, any
 information about that nick which you are allowed to see is presented. A
 comma (',') separated list of nicknames may be given.

 The latter version sends the query to a specific server. It is useful if
 you want to know how long the user in question has been idle as only local
 server (ie. the server the user is directly connected to) knows that
 information, while everything else is globally known.

 Numeric Replies:

            ERR_NOSUCHSERVER                ERR_NONICKNAMEGIVEN

            RPL_WHOISUSER                   RPL_WHOISCHANNELS

            RPL_WHOISCHANNELS               RPL_WHOISSERVER

            RPL_AWAY                        RPL_WHOISOPERATOR

            RPL_WHOISIDLE                   ERR_NOSUCHNICK

            RPL_ENDOFWHOIS

 Examples:

    WHOIS wiz                       ; return available user information

                                    about nick WiZ

    WHOIS eff.org trillian          ; ask server eff.org for user

                                    information about trillian

 4.5.3 Whowas

 Command: WHOWAS
 Parameters: <nickname> [<count> [<server>]]

 Whowas asks for information about a nickname which no longer exists. This
 may either be due to a nickname change or the user leaving IRC. In
 response to this query, the server searches through its nickname history,
 looking for any nicks which are lexically the same (no wild card matching
 here). The history is searched backward, returning the most recent entry
 first. If there are multiple entries, up to <count> replies will be
 returned (or all of them if no <count> parameter is given). If a
 non-positive number is passed as being <count>, then a full search is
 done.

 Numeric Replies:

            ERR_NONICKNAMEGIVEN             ERR_WASNOSUCHNICK

            RPL_WHOWASUSER                  RPL_WHOISSERVER

            RPL_ENDOFWHOWAS

 Examples:

    WHOWAS Wiz                      ; return all information in the nick

                                    history about nick "WiZ";

    WHOWAS Mermaid 9                ; return at most, the 9 most recent

                                    entries in the nick history for

                                    "Mermaid";

    WHOWAS Trillian 1 *.edu         ; return the most recent history for

                                    "Trillian" from the first server found

                                    to match "*.edu".

 4.6 Miscellaneous messages

 Messages in this category do not fit into any of the above categories but
 are nonetheless still a part of and required by the protocol.

 4.6.1 Kill message

 Command: KILL
 Parameters: <nickname> <comment>

 The KILL message is used to cause a client-server connection to be closed
 by the server which has the actual connection. KILL is used by servers
 when they encounter a duplicate entry in the list of valid nicknames and
 is used to remove both entries. It is also available to operators.

 Clients which have automatic reconnect algorithms effectively make this
 command useless since the disconnection is only brief. It does however
 break the flow of data and can be used to stop large amounts of being
 abused, any user may elect to receive KILL messages generated for others
 to keep an 'eye' on would be trouble spots.

 In an arena where nicknames are required to be globally unique at all
 times, KILL messages are sent whenever 'duplicates' are detected (that is
 an attempt to register two users with the same nickname) in the hope that
 both of them will disappear and only 1 reappear.

 The comment given must reflect the actual reason for the KILL. For
 server-generated KILLs it usually is made up of details concerning the
 origins of the two conflicting nicknames. For users it is left up to them
 to provide an adequate reason to satisfy others who see it. To
 prevent/discourage fake KILLs from being generated to hide the identify of
 the KILLer, the comment also shows a 'kill-path' which is updated by each
 server it passes through, each prepending its name to the path.

 Numeric Replies:

            ERR_NOPRIVILEGES                ERR_NEEDMOREPARAMS

            ERR_NOSUCHNICK                  ERR_CANTKILLSERVER

 KILL David (csd.bu.edu <- tolsun.oulu.fi)

                                    ; Nickname collision between csd.bu.edu

                                    and tolson.oulu.fi

 NOTE:
 It is recommended that only Operators be allowed to kill other users with
 KILL message. In an ideal world not even operators would need to do this
 and it would be left to servers to deal with.

 4.6.2 Ping message

 Command: PING
 Parameters: <server1> [<server2>]

 The PING message is used to test the presence of an active client at the
 other end of the connection. A PING message is sent at regular intervals
 if no other activity detected coming from a connection. If a connection
 fails to respond to a PING command within a set amount of time, that
 connection is closed.

 Any client which receives a PING message must respond to <server1> (server
 which sent the PING message out) as quickly as possible with an
 appropriate PONG message to indicate it is still there and alive. Servers
 should not respond to PING commands but rely on PINGs from the other end
 of the connection to indicate the connection is alive. If the <server2>
 parameter is specified, the PING message gets forwarded there.

 Numeric Replies:

 ERR_NOORIGIN ERR_NOSUCHSERVER

 Examples:

    PING tolsun.oulu.fi             ; server sending a PING message to

                                    another server to indicate it is still

                                    alive.

    PING WiZ                        ; PING message being sent to nick WiZ

 4.6.3 Pong message

 Command: PONG
 Parameters: <daemon> [<daemon2>]

 PONG message is a reply to ping message. If parameter <daemon2> is given
 this message must be forwarded to given daemon. The <daemon> parameter is
 the name of the daemon who has responded to PING message and generated
 this message.

 Numeric Replies:

 ERR_NOORIGIN ERR_NOSUCHSERVER

 Examples:

 PONG csd.bu.edu tolsun.oulu.fi ; PONG message from csd.bu.edu to

 tolsun.oulu.fi

 4.6.4 Error

 Command: ERROR
 Parameters: <error message>

 The ERROR command is for use by servers when reporting a serious or fatal
 error to its operators. It may also be sent from one server to another but
 must not be accepted from any normal unknown clients.

 An ERROR message is for use for reporting errors which occur with a
 server-to-server link only. An ERROR message is sent to the server at the
 other end (which sends it to all of its connected operators) and to all
 operators currently connected. It is not to be passed onto any other
 servers by a server if it is received from a server.

 When a server sends a received ERROR message to its operators, the message
 should be encapsulated inside a NOTICE message, indicating that the client
 was not responsible for the error.

 Numerics:

 None.

 Examples:

 ERROR :Server *.fi already exists; ERROR message to the other server

 which caused this error.

 NOTICE WiZ :ERROR from csd.bu.edu -- Server *.fi already exists

                                    ; Same ERROR message as above but sent

                                    to user WiZ on the other server.

 5. OPTIONALS

 This section describes OPTIONAL messages. They are not required in a
 working server implementation of the protocol described herein. In the
 absence of the option, an error reply message must be generated or an
 unknown command error. If the message is destined for another server to
 answer then it must be passed on (elementary parsing required) The
 allocated numerics for this are listed with the messages below.

 5.1 Away

 Command: AWAY
 Parameters: [message]

 With the AWAY message, clients can set an automatic reply string for any
 PRIVMSG commands directed at them (not to a channel they are on). The
 automatic reply is sent by the server to client sending the PRIVMSG
 command. The only replying server is the one to which the sending client
 is connected to.

 The AWAY message is used either with one parameter (to set an AWAY
 message) or with no parameters (to remove the AWAY message).

 Numeric Replies:

 RPL_UNAWAY RPL_NOWAWAY

 Examples:

 AWAY :Gone to lunch. Back in 5 ; set away message to "Gone to lunch.

 Back in 5".

 :WiZ AWAY ; unmark WiZ as being away.

 5.2 Rehash message

 Command: REHASH
 Parameters: None

 The rehash message can be used by the operator to force the server to
 re-read and process its configuration file.

 Numeric Replies:

 RPL_REHASHING ERR_NOPRIVILEGES

 Examples:

 REHASH                          ; message from client with operator

                                 status to server asking it to reread its

                                 configuration file.

 5.3 Restart message

 Command: RESTART
 Parameters: None

 The restart message can only be used by an operator to force a server
 restart itself. This message is optional since it may be viewed as a risk
 to allow arbitrary people to connect to a server as an operator and
 execute this command, causing (at least) a disruption to service.

 The RESTART command must always be fully processed by the server to which
 the sending client is connected and not be passed onto other connected
 servers.

 Numeric Replies:

 ERR_NOPRIVILEGES

 Examples:

 RESTART ; no parameters required.

 5.4 Summon message

 Command: SUMMON
 Parameters: <user> [<server>]

 The SUMMON command can be used to give users who are on a host running an
 IRC server a message asking them to please join IRC. This message is only
 sent if the target server (a) has SUMMON enabled, (b) the user is logged
 in and (c) the server process can write to the user's tty (or similar).

 If no <server> parameter is given it tries to summon <user> from the
 server the client is connected to is assumed as the target.

 If summon is not enabled in a server, it must return the
 ERR_SUMMONDISABLED numeric and pass the summon message onwards.

 Numeric Replies:

            ERR_NORECIPIENT                 ERR_FILEERROR

            ERR_NOLOGIN                     ERR_NOSUCHSERVER

            RPL_SUMMONING

 Examples:

 SUMMON jto ; summon user jto on the server's host

    SUMMON jto tolsun.oulu.fi       ; summon user jto on the host which a

                                    server named "tolsun.oulu.fi" is

                                    running.

 5.5 Users

 Command: USERS
 Parameters: [<server>]

 The USERS command returns a list of users logged into the server in a
 similar format to who(1), rusers(1) and finger(1). Some people may disable
 this command on their server for security related reasons. If disabled,
 the correct numeric must be returned to indicate this.

 Numeric Replies:

            ERR_NOSUCHSERVER                ERR_FILEERROR

            RPL_USERSSTART                  RPL_USERS

            RPL_NOUSERS                     RPL_ENDOFUSERS

            ERR_USERSDISABLED

 Disabled Reply:

 ERR_USERSDISABLED

 Examples:

 USERS eff.org                   ; request a list of users logged in on

                                 server eff.org

 :John USERS tolsun.oulu.fi      ; request from John for a list of users

                                 logged in on server tolsun.oulu.fi

 5.6 Operwall message

 Command: WALLOPS
 Parameters: Text to be sent to all operators currently online

 Sends a message to all operators currently online. After implementing
 WALLOPS as a user command it was found that it was often and commonly
 abused as a means of sending a message to a lot of people (much similar to
 WALL). Due to this it is recommended that the current implementation of
 WALLOPS be used as an example by allowing and recognising only servers as
 the senders of WALLOPS.

 Numeric Replies:

 ERR_NEEDMOREPARAMS

 Examples:

 :csd.bu.edu WALLOPS :Connect '*.uiuc.edu 6667' from Joshua; WALLOPS

                                    message from csd.bu.edu announcing a

                                    CONNECT message it received and acted

                                    upon from Joshua.

 5.7 Userhost message

 Command: USERHOST
 Parameters: <nickname>{<space><nickname>}

 The USERHOST command takes a list of up to 5 nicknames, each separated by
 a space character and returns a list of information about each nickname
 that it found. The returned list has each reply separated by a space.

 Numeric Replies:

 RPL_USERHOST ERR_NEEDMOREPARAMS

 Examples:

 USERHOST Wiz Michael Marty p ;USERHOST request for information on

 nicks "Wiz", "Michael", "Marty" and "p"

 5.8 Ison message

 Command: ISON
 Parameters: <nickname>{<space><nickname>}

 The ISON command was implemented to provide a quick and efficient means to
 get a response about whether a given nickname was currently on IRC. ISON
 only takes one (1) parameter: a space-separated list of nicks. For each
 nickname in the list that is present, the server adds that to its reply
 string. Thus the reply string may return empty (none of the given nicks
 are present), an exact copy of the parameter string (all of them present)
 or as any other subset of the set of nicks given in the parameter. The
 only limit on the number of nicks that may be checked is that the combined
 length must not be too large as to cause the server to chop it off so it
 fits in 512 characters.

 ISON is only be processed by the server local to the client sending the
 command and thus not passed onto other servers for further processing.

 Numeric Replies:

 RPL_ISON ERR_NEEDMOREPARAMS

 Examples:

 ISON phone trillian WiZ jarlek Avalon Angel Monstah

 ; Sample ISON request for 7 nicks.

 The following is a list of numeric replies which are generated in response
 to the commands given above. Each numeric is given with its number, name
 and reply string.

 6.1 Error Replies.

         401     ERR_NOSUCHNICK

                         "<nickname> :No such nick/channel"

                 - Used to indicate the nickname parameter supplied to a

                   command is currently unused.

         402     ERR_NOSUCHSERVER

                         "<server name> :No such server"

                 - Used to indicate the server name given currently

                   doesn't exist.

         403     ERR_NOSUCHCHANNEL

                         "<channel name> :No such channel"

                 - Used to indicate the given channel name is invalid.

         404     ERR_CANNOTSENDTOCHAN

                         "<channel name> :Cannot send to channel"

                 - Sent to a user who is either (a) not on a channel

                   which is mode +n or (b) not a chanop (or mode +v) on

                   a channel which has mode +m set and is trying to send

                   a PRIVMSG message to that channel.

         405     ERR_TOOMANYCHANNELS

                         "<channel name> :You have joined too many \

                          channels"

                 - Sent to a user when they have joined the maximum

                   number of allowed channels and they try to join

                   another channel.

         406     ERR_WASNOSUCHNICK

                         "<nickname> :There was no such nickname"

                 - Returned by WHOWAS to indicate there is no history

                   information for that nickname.

         407     ERR_TOOMANYTARGETS

                         "<target> :Duplicate recipients. No message \

                          delivered"

         408     ERR_

                 - Returned to a client which is attempting to send a

                   PRIVMSG/NOTICE using the user@host destination format

                   and for a user@host which has several occurrences.

         409     ERR_NOORIGIN

                         ":No origin specified"

                 - PING or PONG message missing the originator parameter

                   which is required since these commands must work

                   without valid prefixes.

         411     ERR_NORECIPIENT

                         ":No recipient given (<command>)"

         412     ERR_NOTEXTTOSEND

                         ":No text to send"

         413     ERR_NOTOPLEVEL

                         "<mask> :No toplevel domain specified"

         414     ERR_WILDTOPLEVEL

                         "<mask> :Wildcard in toplevel domain"

                 - 412 - 414 are returned by PRIVMSG to indicate that

                   the message wasn't delivered for some reason.

                   ERR_NOTOPLEVEL and ERR_WILDTOPLEVEL are errors that

                   are returned when an invalid use of

                   "PRIVMSG $<server>" or "PRIVMSG #<host>" is attempted.

         421     ERR_UNKNOWNCOMMAND

                         "<command> :Unknown command"

                 - Returned to a registered client to indicate that the

                   command sent is unknown by the server.

         422     ERR_NOMOTD

                         ":MOTD File is missing"

                 - Server's MOTD file could not be opened by the server.

         423     ERR_NOADMININFO

                         "<server> :No administrative info available"

                 - Returned by a server in response to an ADMIN message

                   when there is an error in finding the appropriate

                   information.

         424     ERR_FILEERROR

                 ":File error doing <file op> on <file>"

                   Generic error message used to report a failed file

                   operation during the processing of a message.

         431     ERR_NONICKNAMEGIVEN

                         ":No nickname given"

                 - Returned when a nickname parameter expected for a

                   command and isn't found.

         432     ERR_ERRONEUSNICKNAME

                         "<nick> :Erroneus nickname"

                 - Returned after receiving a NICK message which contains

                   characters which do not fall in the defined set.  See

                   section x.x.x for details on valid nicknames.

         433     ERR_NICKNAMEINUSE

                         "<nick> :Nickname is already in use"

                 - Returned when a NICK message is processed that results

                   in an attempt to change to a currently existing

                   nickname.

         436     ERR_NICKCOLLISION

                         "<nick> :Nickname collision KILL"

                 - Returned by a server to a client when it detects a

                   nickname collision (registered of a NICK that

                   already exists by another server).

         441     ERR_USERNOTINCHANNEL

                         "<nick> <channel> :They aren't on that channel"

                 - Returned by the server to indicate that the target

                   user of the command is not on the given channel.

         442     ERR_NOTONCHANNEL

                         "<channel> :You're not on that channel"

                 - Returned by the server whenever a client tries to

                   perform a channel effecting command for which the

                   client isn't a member.

         443     ERR_USERONCHANNEL

                         "<user> <channel> :is already on channel"

                 - Returned when a client tries to invite a user to a

                   channel they are already on.

         444     ERR_NOLOGIN

                         "<user> :User not logged in"

                 - Returned by the summon after a SUMMON command for a

                   user was unable to be performed since they were not

                   logged in.

         445     ERR_SUMMONDISABLED

                         ":SUMMON has been disabled"

                 - Returned as a response to the SUMMON command.  Must be

                   returned by any server which does not implement it.

         446     ERR_USERSDISABLED

                         ":USERS has been disabled"

                 - Returned as a response to the USERS command.  Must be

                   returned by any server which does not implement it.

         451     ERR_NOTREGISTERED

                         ":You have not registered"

                 - Returned by the server to indicate that the client

                   must be registered before the server will allow it

                   to be parsed in detail.

         461     ERR_NEEDMOREPARAMS

                         "<command> :Not enough parameters"

                 - Returned by the server by numerous commands to

                   indicate to the client that it didn't supply enough

                   parameters.

         462     ERR_ALREADYREGISTRED

                         ":You may not reregister"

                 - Returned by the server to any link which tries to

                   change part of the registered details (such as

                   password or user details from second USER message).

         463     ERR_NOPERMFORHOST

                         ":Your host isn't among the privileged"

                 - Returned to a client which attempts to register with

                   a server which does not been setup to allow

                   connections from the host the attempted connection

                   is tried.

         464     ERR_PASSWDMISMATCH

                         ":Password incorrect"

                 - Returned to indicate a failed attempt at registering

                   a connection for which a password was required and

                   was either not given or incorrect.

         465     ERR_YOUREBANNEDCREEP

                         ":You are banned from this server"

                 - Returned after an attempt to connect and register

                   yourself with a server which has been setup to

                   explicitly deny connections to you.

         467     ERR_KEYSET

                         "<channel> :Channel key already set"

         471     ERR_CHANNELISFULL

                         "<channel> :Cannot join channel (+l)"

         472     ERR_UNKNOWNMODE

                         "<char> :is unknown mode char to me"

         473     ERR_INVITEONLYCHAN

                         "<channel> :Cannot join channel (+i)"

         474     ERR_BANNEDFROMCHAN

                         "<channel> :Cannot join channel (+b)"

         475     ERR_BADCHANNELKEY

                         "<channel> :Cannot join channel (+k)"

         481     ERR_NOPRIVILEGES

                         ":Permission Denied- You're not an IRC operator"

                 - Any command requiring operator privileges to operate

                   must return this error to indicate the attempt was

                   unsuccessful.

         482     ERR_CHANOPRIVSNEEDED

                         "<channel> :You're not channel operator"

                 - Any command requiring 'chanop' privileges (such as

                   MODE messages) must return this error if the client

                   making the attempt is not a chanop on the specified

                   channel.

         483     ERR_CANTKILLSERVER

                         ":You cant kill a server!"

                 - Any attempts to use the KILL command on a server

                   are to be refused and this error returned directly

                   to the client.

         491     ERR_NOOPERHOST

                         ":No O-lines for your host"

                 - If a client sends an OPER message and the server has

                   not been configured to allow connections from the

                   client's host as an operator, this error must be

                   returned.

         501     ERR_UMODEUNKNOWNFLAG

                         ":Unknown MODE flag"

                 - Returned by the server to indicate that a MODE

                   message was sent with a nickname parameter and that

                   the a mode flag sent was not recognized.

         502     ERR_USERSDONTMATCH

                         ":Cant change mode for other users"

                 - Error sent to any user trying to view or change the

                   user mode for a user other than themselves.

 6.2 Command responses.

         300     RPL_NONE

                         Dummy reply number. Not used.

         302     RPL_USERHOST

                         ":[<reply>{<space><reply>}]"

                 - Reply format used by USERHOST to list replies to

                   the query list.  The reply string is composed as

                   follows:

                   <reply> ::= <nick>['*'] '=' <'+'|'-'><hostname>

                   The '*' indicates whether the client has registered

                   as an Operator.  The '-' or '+' characters represent

                   whether the client has set an AWAY message or not

                   respectively.

         303     RPL_ISON

                         ":[<nick> {<space><nick>}]"

                 - Reply format used by ISON to list replies to the

                   query list.

         301     RPL_AWAY

                         "<nick> :<away message>"

         305     RPL_UNAWAY

                         ":You are no longer marked as being away"

         306     RPL_NOWAWAY

                         ":You have been marked as being away"

                 - These replies are used with the AWAY command (if

                   allowed).  RPL_AWAY is sent to any client sending a

                   PRIVMSG to a client which is away.  RPL_AWAY is only

                   sent by the server to which the client is connected.

                   Replies RPL_UNAWAY and RPL_NOWAWAY are sent when the

                   client removes and sets an AWAY message.

         311     RPL_WHOISUSER

                         "<nick> <user> <host> * :<real name>"

         312     RPL_WHOISSERVER

                         "<nick> <server> :<server info>"

         313     RPL_WHOISOPERATOR

                         "<nick> :is an IRC operator"

         317     RPL_WHOISIDLE

                         "<nick> <integer> :seconds idle"

         318     RPL_ENDOFWHOIS

                         "<nick> :End of /WHOIS list"

         319     RPL_WHOISCHANNELS

                         "<nick> :{[@|+]<channel><space>}"

                 - Replies 311 - 313, 317 - 319 are all replies

                   generated in response to a WHOIS message.  Given that

                   there are enough parameters present, the answering

                   server must either formulate a reply out of the above

                   numerics (if the query nick is found) or return an

                   error reply.  The '*' in RPL_WHOISUSER is there as

                   the literal character and not as a wild card.  For

                   each reply set, only RPL_WHOISCHANNELS may appear

                   more than once (for long lists of channel names).

                   The '@' and '+' characters next to the channel name

                   indicate whether a client is a channel operator or

                   has been granted permission to speak on a moderated

                   channel.  The RPL_ENDOFWHOIS reply is used to mark

                   the end of processing a WHOIS message.

         314     RPL_WHOWASUSER

                         "<nick> <user> <host> * :<real name>"

         369     RPL_ENDOFWHOWAS

                         "<nick> :End of WHOWAS"

                 - When replying to a WHOWAS message, a server must use

                   the replies RPL_WHOWASUSER, RPL_WHOISSERVER or

                   ERR_WASNOSUCHNICK for each nickname in the presented

                   list.  At the end of all reply batches, there must

                   be RPL_ENDOFWHOWAS (even if there was only one reply

                   and it was an error).

         321     RPL_LISTSTART

                         "Channel :Users  Name"

         322     RPL_LIST

                         "<channel> <# visible> :<topic>"

         323     RPL_LISTEND

                         ":End of /LIST"

                 - Replies RPL_LISTSTART, RPL_LIST, RPL_LISTEND mark

                   the start, actual replies with data and end of the

                   server's response to a LIST command.  If there are

                   no channels available to return, only the start

                   and end reply must be sent.

         324     RPL_CHANNELMODEIS

                         "<channel> <mode> <mode params>"

         331     RPL_NOTOPIC

                         "<channel> :No topic is set"

         332     RPL_TOPIC

                         "<channel> :<topic>"

                 - When sending a TOPIC message to determine the

                   channel topic, one of two replies is sent.  If

                   the topic is set, RPL_TOPIC is sent back else

                   RPL_NOTOPIC.

         341     RPL_INVITING

                         "<channel> <nick>"

                 - Returned by the server to indicate that the

                   attempted INVITE message was successful and is

                   being passed onto the end client.

         342     RPL_SUMMONING

                         "<user> :Summoning user to IRC"

                 - Returned by a server answering a SUMMON message to

                   indicate that it is summoning that user.

         351     RPL_VERSION

                         "<version>.<debuglevel> <server> :<comments>"

                 - Reply by the server showing its version details.

                   The <version> is the version of the software being

                   used (including any patchlevel revisions) and the

                   <debuglevel> is used to indicate if the server is

                   running in "debug mode".

                   The "comments" field may contain any comments about

                   the version or further version details.

         352     RPL_WHOREPLY

                         "<channel> <user> <host> <server> <nick> \

                          <H|G>[*][@|+] :<hopcount> <real name>"

         315     RPL_ENDOFWHO

                         "<name> :End of /WHO list"

                 - The RPL_WHOREPLY and RPL_ENDOFWHO pair are used

                   to answer a WHO message.  The RPL_WHOREPLY is only

                   sent if there is an appropriate match to the WHO

                   query.  If there is a list of parameters supplied

                   with a WHO message, a RPL_ENDOFWHO must be sent

                   after processing each list item with <name> being

                   the item.

         353     RPL_NAMREPLY

                         "<channel> :[[@|+]<nick> [[@|+]<nick> [...]]]"

         366     RPL_ENDOFNAMES

                         "<channel> :End of /NAMES list"

                 - To reply to a NAMES message, a reply pair consisting

                   of RPL_NAMREPLY and RPL_ENDOFNAMES is sent by the

                   server back to the client.  If there is no channel

                   found as in the query, then only RPL_ENDOFNAMES is

                   returned.  The exception to this is when a NAMES

                   message is sent with no parameters and all visible

                   channels and contents are sent back in a series of

                   RPL_NAMEREPLY messages with a RPL_ENDOFNAMES to mark

                   the end.

         364     RPL_LINKS

                         "<mask> <server> :<hopcount> <server info>"

         365     RPL_ENDOFLINKS

                         "<mask> :End of /LINKS list"

                 - In replying to the LINKS message, a server must send

                   replies back using the RPL_LINKS numeric and mark the

                   end of the list using an RPL_ENDOFLINKS reply.

         367     RPL_BANLIST

                         "<channel> <banid>"

         368     RPL_ENDOFBANLIST

                         "<channel> :End of channel ban list"

                   When listing the active 'bans' for a given channel,

                   a server is required to send the list back using the

                   RPL_BANLIST and RPL_ENDOFBANLIST messages.  A separate

                   RPL_BANLIST is sent for each active banid.  After the

                   banids have been listed (or if none present) a

                   RPL_ENDOFBANLIST must be sent.

         371     RPL_INFO

                         ":<string>"

         374     RPL_ENDOFINFO

                         ":End of /INFO list"

                 - A server responding to an INFO message is required to

                   send all its 'info' in a series of RPL_INFO messages

                   with a RPL_ENDOFINFO reply to indicate the end of the

                   replies.

         375     RPL_MOTDSTART

                         ":- <server> Message of the day - "

         372     RPL_MOTD

                         ":- <text>"

         376     RPL_ENDOFMOTD

                         ":End of /MOTD command"

                 - When responding to the MOTD message and the MOTD file

                   is found, the file is displayed line by line, with

                   each line no longer than 80 characters, using

                   RPL_MOTD format replies.  These should be surrounded

                   by a RPL_MOTDSTART (before the RPL_MOTDs) and an

                   RPL_ENDOFMOTD (after).

         381     RPL_YOUREOPER

                         ":You are now an IRC operator"

                 - RPL_YOUREOPER is sent back to a client which has

                   just successfully issued an OPER message and gained

                   operator status.

         382     RPL_REHASHING

                         "<config file> :Rehashing"

                 - If the REHASH option is used and an operator sends

                   a REHASH message, an RPL_REHASHING is sent back to

                   the operator.

         391     RPL_TIME

                         "<server> :<string showing server's local time>"

                   When replying to the TIME message, a server must send

                   the reply using the RPL_TIME format above.  The string

                   showing the time need only contain the correct day and

                   time there.  There is no further requirement for the

                   time string.

         392     RPL_USERSSTART

                         ":UserID   Terminal  Host"

         393     RPL_USERS

                         ":%-8s %-9s %-8s"

         394     RPL_ENDOFUSERS

                         ":End of users"

         395     RPL_NOUSERS

                         ":Nobody logged in"

                 - If the USERS message is handled by a server, the

                   replies RPL_USERSTART, RPL_USERS, RPL_ENDOFUSERS and

                   RPL_NOUSERS are used.  RPL_USERSSTART must be sent

                   first, following by either a sequence of RPL_USERS

                   or a single RPL_NOUSER.  Following this is

                   RPL_ENDOFUSERS.

         200     RPL_TRACELINK

                         "Link <version & debug level> <destination> \

                          <next server>"

         201     RPL_TRACECONNECTING

                         "Try. <class> <server>"

         202     RPL_TRACEHANDSHAKE

                         "H.S. <class> <server>"

         203     RPL_TRACEUNKNOWN

                         "???? <class> [<client IP address in dot form>]"

         204     RPL_TRACEOPERATOR

                         "Oper <class> <nick>"

         205     RPL_TRACEUSER

                         "User <class> <nick>"

         206     RPL_TRACESERVER

                         "Serv <class> <int>S <int>C <server> \

                          <nick!user|*!*>@<host|server>"

         208     RPL_TRACENEWTYPE

                         "<newtype> 0 <client name>"

         261     RPL_TRACELOG

                         "File <logfile> <debug level>"

                 - The RPL_TRACE* are all returned by the server in

                   response to the TRACE message.  How many are

                   returned is dependent on the the TRACE message and

                   whether it was sent by an operator or not.  There

                   is no predefined order for which occurs first.

                   Replies RPL_TRACEUNKNOWN, RPL_TRACECONNECTING and

                   RPL_TRACEHANDSHAKE are all used for connections

                   which have not been fully established and are either

                   unknown, still attempting to connect or in the

                   process of completing the 'server handshake'.

                   RPL_TRACELINK is sent by any server which handles

                   a TRACE message and has to pass it on to another

                   server.  The list of RPL_TRACELINKs sent in

                   response to a TRACE command traversing the IRC

                   network should reflect the actual connectivity of

                   the servers themselves along that path.

                   RPL_TRACENEWTYPE is to be used for any connection

                   which does not fit in the other categories but is

                   being displayed anyway.

         211     RPL_STATSLINKINFO

                         "<linkname> <sendq> <sent messages> \

                          <sent bytes> <received messages> \

                          <received bytes> <time open>"

         212     RPL_STATSCOMMANDS

                         "<command> <count>"

         213     RPL_STATSCLINE

                         "C <host> * <name> <port> <class>"

         214     RPL_STATSNLINE

                         "N <host> * <name> <port> <class>"

         215     RPL_STATSILINE

                         "I <host> * <host> <port> <class>"

         216     RPL_STATSKLINE

                         "K <host> * <username> <port> <class>"

         218     RPL_STATSYLINE

                         "Y <class> <ping frequency> <connect \

                          frequency> <max sendq>"

         219     RPL_ENDOFSTATS

                         "<stats letter> :End of /STATS report"

         241     RPL_STATSLLINE

                         "L <hostmask> * <servername> <maxdepth>"

         242     RPL_STATSUPTIME

                         ":Server Up %d days %d:%02d:%02d"

         243     RPL_STATSOLINE

                         "O <hostmask> * <name>"

         244     RPL_STATSHLINE

                         "H <hostmask> * <servername>"

         221     RPL_UMODEIS

                         "<user mode string>"

                           To answer a query about a client's own mode,

                           RPL_UMODEIS is sent back.

         251     RPL_LUSERCLIENT

                         ":There are <integer> users and <integer> \

                          invisible on <integer> servers"

         252     RPL_LUSEROP

                         "<integer> :operator(s) online"

         253     RPL_LUSERUNKNOWN

                         "<integer> :unknown connection(s)"

         254     RPL_LUSERCHANNELS

                         "<integer> :channels formed"

         255     RPL_LUSERME

                         ":I have <integer> clients and <integer> \

                           servers"

                         - In processing an LUSERS message, the server

                           sends a set of replies from RPL_LUSERCLIENT,

                           RPL_LUSEROP, RPL_USERUNKNOWN,

                           RPL_LUSERCHANNELS and RPL_LUSERME.  When

                           replying, a server must send back

                           RPL_LUSERCLIENT and RPL_LUSERME.  The other

                           replies are only sent back if a non-zero count

                           is found for them.

         256     RPL_ADMINME

                         "<server> :Administrative info"

         257     RPL_ADMINLOC1

                         ":<admin info>"

         258     RPL_ADMINLOC2

                         ":<admin info>"

         259     RPL_ADMINEMAIL

                         ":<admin info>"

                         - When replying to an ADMIN message, a server

                           is expected to use replies RLP_ADMINME

                           through to RPL_ADMINEMAIL and provide a text

                           message with each.  For RPL_ADMINLOC1 a

                           description of what city, state and country

                           the server is in is expected, followed by

                           details of the university and department

                           (RPL_ADMINLOC2) and finally the administrative

                           contact for the server (an email address here

                           is required) in RPL_ADMINEMAIL.

 6.3 Reserved numerics.

 These numerics are not described above since they fall into one of the
 following categories:

    * no longer in use;
    * reserved for future planned use;
    * in current use but are part of a non-generic 'feature' of the current
      IRC server.

         209     RPL_TRACECLASS          217     RPL_STATSQLINE

         231     RPL_SERVICEINFO         232     RPL_ENDOFSERVICES

         233     RPL_SERVICE             234     RPL_SERVLIST

         235     RPL_SERVLISTEND

         316     RPL_WHOISCHANOP         361     RPL_KILLDONE

         362     RPL_CLOSING             363     RPL_CLOSEEND

         373     RPL_INFOSTART           384     RPL_MYPORTIS

         466     ERR_YOUWILLBEBANNED     476     ERR_BADCHANMASK

         492     ERR_NOSERVICEHOST

 7. Client and server authentication

 Clients and servers are both subject to the same level of authentication.
 For both, an IP number to hostname lookup (and reverse check on this) is
 performed for all connections made to the server. Both connections are
 then subject to a password check (if there is a password set for that
 connection). These checks are possible on all connections although the
 password check is only commonly used with servers.

 An additional check that is becoming of more and more common is that of
 the username responsible for making the connection. Finding the username
 of the other end of the connection typically involves connecting to an
 authentication server such as IDENT as described in RFC 1413.

 Given that without passwords it is not easy to reliably determine who is
 on the other end of a network connection, use of passwords is strongly
 recommended on inter-server connections in addition to any other measures
 such as using an ident server.

 8. Current implementations

 The only current implementation of this protocol is the IRC server,
 version 2.8. Earlier versions may implement some or all of the commands
 described by this document with NOTICE messages replacing many of the
 numeric replies. Unfortunately, due to backward compatibility
 requirements, the implementation of some parts of this document varies
 with what is laid out. On notable difference is:

    * recognition that any LF or CR anywhere in a message marks the end of
      that message (instead of requiring CR-LF);

 The rest of this section deals with issues that are mostly of importance
 to those who wish to implement a server but some parts also apply directly
 to clients as well.

 8.1 Network protocol: TCP - why it is best used here.

 IRC has been implemented on top of TCP since TCP supplies a reliable
 network protocol which is well suited to this scale of conferencing. The
 use of multicast IP is an alternative, but it is not widely available or
 supported at the present time.

 8.1.1 Support of Unix sockets

 Given that Unix domain sockets allow listen/connect operations, the
 current implementation can be configured to listen and accept both client
 and server connections on a Unix domain socket. These are recognized as
 sockets where the hostname starts with a '/'.

 When providing any information about the connections on a Unix domain
 socket, the server is required to supplant the actual hostname in place of
 the pathname unless the actual socket name is being asked for.

 8.2 Command Parsing

 To provide useful 'non-buffered' network IO for clients and servers, each
 connection is given its own private 'input buffer' in which the results of
 the most recent read and parsing are kept. A buffer size of 512 bytes is
 used so as to hold 1 full message, although, this will usually hold
 several commands. The private buffer is parsed after every read operation
 for valid messages. When dealing with multiple messages from one client in
 the buffer, care should be taken in case one happens to cause the client
 to be 'removed'.

 8.3 Message delivery

 It is common to find network links saturated or hosts to which you are
 sending data unable to send data. Although Unix typically handles this
 through the TCP window and internal buffers, the server often has large
 amounts of data to send (especially when a new server-server link forms)
 and the small buffers provided in the kernel are not enough for the
 outgoing queue. To alleviate this problem, a "send queue" is used as a
 FIFO queue for data to be sent. A typical "send queue" may grow to 200
 Kbytes on a large IRC network with a slow network connection when a new
 server connects.

 When polling its connections, a server will first read and parse all
 incoming data, queuing any data to be sent out. When all available input
 is processed, the queued data is sent. This reduces the number of write()
 system calls and helps TCP make bigger packets.

 8.4 Connection 'Liveness'

 To detect when a connection has died or become unresponsive, the server
 must ping each of its connections that it doesn't get a response from in a
 given amount of time.

 If a connection doesn't respond in time, its connection is closed using
 the appropriate procedures. A connection is also dropped if its sendq
 grows beyond the maximum allowed, because it is better to close a slow
 connection than have a server process block.

 8.5 Establishing a server to client connection

 Upon connecting to an IRC server, a client is sent the MOTD (if present)
 as well as the current user/server count (as per the LUSER command). The
 server is also required to give an unambiguous message to the client which
 states its name and version as well as any other introductory messages
 which may be deemed appropriate.

 After dealing with this, the server must then send out the new user's
 nickname and other information as supplied by itself (USER command) and as
 the server could discover (from DNS/authentication servers). The server
 must send this information out with NICK first followed by USER.

 8.6 Establishing a server-server connection.

 The process of establishing of a server-to-server connection is fraught
 with danger since there are many possible areas where problems can occur -
 the least of which are race conditions.

 After a server has received a connection following by a PASS/SERVER pair
 which were recognised as being valid, the server should then reply with
 its own PASS/SERVER information for that connection as well as all of the
 other state information it knows about as described below.

 When the initiating server receives a PASS/SERVER pair, it too then checks
 that the server responding is authenticated properly before accepting the
 connection to be that server.

 8.6.1 Server exchange of state information when connecting

 The order of state information being exchanged between servers is
 essential. The required order is as follows:

    * all known other servers;
    * all known user information;
    * all known channel information.

 Information regarding servers is sent via extra SERVER messages, user
 information with NICK/USER/MODE/JOIN messages and channels with MODE
 messages.

 NOTE: channel topics are *NOT* exchanged here because the TOPIC command
 overwrites any old topic information, so at best, the two sides of the
 connection would exchange topics.

 By passing the state information about servers first, any collisions with
 servers that already exist occur before nickname collisions due to a
 second server introducing a particular nickname. Due to the IRC network
 only being able to exist as an acyclic graph, it may be possible that the
 network has already reconnected in another location, the place where the
 collision occurs indicating where the net needs to split.

 8.7 Terminating server-client connections

 When a client connection closes, a QUIT message is generated on behalf of
 the client by the server to which the client connected. No other message
 is to be generated or used.

 8.8 Terminating server-server connections

 If a server-server connection is closed, either via a remotely generated
 SQUIT or 'natural' causes, the rest of the connected IRC network must have
 its information updated with by the server which detected the closure. The
 server then sends a list of SQUITs (one for each server behind that
 connection) and a list of QUITs (again, one for each client behind that
 connection).

 8.9 Tracking nickname changes

 All IRC servers are required to keep a history of recent nickname changes.
 This is required to allow the server to have a chance of keeping in touch
 of things when nick-change race conditions occur with commands which
 manipulate them. Commands which must trace nick changes are:

    * KILL (the nick being killed)
    * MODE (+/- o,v)
    * KICK (the nick being kicked)

 No other commands are to have nick changes checked for.

 In the above cases, the server is required to first check for the
 existence of the nickname, then check its history to see who that nick
 currently belongs to (if anyone!). This reduces the chances of race
 conditions but they can still occur with the server ending up affecting
 the wrong client. When performing a change trace for an above command it
 is recommended that a time range be given and entries which are too old
 ignored.

 For a reasonable history, a server should be able to keep previous
 nickname for every client it knows about if they all decided to change.
 This size is limited by other factors (such as memory, etc).

 8.10 Flood control of clients

 With a large network of interconnected IRC servers, it is quite easy for
 any single client attached to the network to supply a continuous stream of
 messages that result in not only flooding the network, but also degrading
 the level of service provided to others. Rather than require every
 'victim' to be provide their own protection, flood protection was written
 into the server and is applied to all clients except services. The current
 algorithm is as follows:

    * check to see if client's `message timer' is less than current time
      (set to be equal if it is);
    * read any data present from the client;
    * while the timer is less than ten seconds ahead of the current time,
      parse any present messages and penalize the client by 2 seconds for
      each message;

 which in essence means that the client may send 1 message every 2 seconds
 without being adversely affected.

 8.11 Non-blocking lookups

 In a real-time environment, it is essential that a server process do as
 little waiting as possible so that all the clients are serviced fairly.
 Obviously this requires non-blocking IO on all network read/write
 operations. For normal server connections, this was not difficult, but
 there are other support operations that may cause the server to block
 (such as disk reads). Where possible, such activity should be performed
 with a short timeout.

 8.11.1 Hostname (DNS) lookups

 Using the standard resolver libraries from Berkeley and others has meant
 large delays in some cases where replies have timed out. To avoid this, a
 separate set of DNS routines were written which were setup for
 non-blocking IO operations and then polled from within the main server IO
 loop.

 8.11.2 Username (Ident) lookups

 Although there are numerous ident libraries for use and inclusion into
 other programs, these caused problems since they operated in a synchronous
 manner and resulted in frequent delays. Again the solution was to write a
 set of routines which would cooperate with the rest of the server and work
 using non-blocking IO.

 8.12 Configuration File

 To provide a flexible way of setting up and running the server, it is
 recommended that a configuration file be used which contains instructions
 to the server on the following:

    * which hosts to accept client connections from;
    * which hosts to allow to connect as servers;
    * which hosts to connect to (both actively and passively);
    * information about where the server is (university, city/state,
      company are examples of this);
    * who is responsible for the server and an email address at which they
      can be contacted;
    * hostnames and passwords for clients which wish to be given access to
      restricted operator commands.

 In specifying hostnames, both domain names and use of the 'dot' notation
 (127.0.0.1) should both be accepted. It must be possible to specify the
 password to be used/accepted for all outgoing and incoming connections
 (although the only outgoing connections are those to other servers).

 The above list is the minimum requirement for any server which wishes to
 make a connection with another server. Other items which may be of use
 are:

    * specifying which servers other server may introduce;
    * how deep a server branch is allowed to become;
    * hours during which clients may connect.

 8.12.1 Allowing clients to connect

 A server should use some sort of 'access control list' (either in the
 configuration file or elsewhere) that is read at startup and used to
 decide what hosts clients may use to connect to it.

 Both 'deny' and 'allow' should be implemented to provide the required
 flexibility for host access control.

 8.12.2 Operators

 The granting of operator privileges to a disruptive person can have dire
 consequences for the well-being of the IRC net in general due to the
 powers given to them. Thus, the acquisition of such powers should not be
 very easy. The current setup requires two 'passwords' to be used although
 one of them is usually easy guessed. Storage of oper passwords in
 configuration files is preferable to hard coding them in and should be
 stored in a crypted format (ie using crypt(3) from Unix) to prevent easy
 theft.

 8.12.3 Allowing servers to connect

 The interconnection of server is not a trivial matter: a bad connection
 can have a large impact on the usefulness of IRC. Thus, each server should
 have a list of servers to which it may connect and which servers may
 connect to it. Under no circumstances should a server allow an arbitrary
 host to connect as a server. In addition to which servers may and may not
 connect, the configuration file should also store the password and other
 characteristics of that link.

 8.12.4 Administrivia

 To provide accurate and valid replies to the ADMIN command (see section
 4.3.7), the server should find the relevant details in the configuration.

 8.13 Channel membership

 The current server allows any registered local user to join upto 10
 different channels. There is no limit imposed on non-local users so that
 the server remains (reasonably) consistant with all others on a channel
 membership basis

 9. Current problems

 There are a number of recognized problems with this protocol, all of which
 hope to be solved sometime in the near future during its rewrite.
 Currently, work is underway to find working solutions to these problems.

 9.1 Scalability

 It is widely recognized that this protocol does not scale sufficiently
 well when used in a large arena. The main problem comes from the
 requirement that all servers know about all other servers and users and
 that information regarding them be updated as soon as it changes. It is
 also desirable to keep the number of servers low so that the path length
 between any two points is kept minimal and the spanning tree as strongly
 branched as possible.

 9.2 Labels

 The current IRC protocol has 3 types of labels: the nickname, the channel
 name and the server name. Each of the three types has its own domain and
 no duplicates are allowed inside that domain. Currently, it is possible
 for users to pick the label for any of the three, resulting in collisions.
 It is widely recognized that this needs reworking, with a plan for unique
 names for channels and nicks that don't collide being desirable as well as
 a solution allowing a cyclic tree.

 9.2.1 Nicknames

 The idea of the nickname on IRC is very convenient for users to use when
 talking to each other outside of a channel, but there is only a finite
 nickname space and being what they are, its not uncommon for several
 people to want to use the same nick. If a nickname is chosen by two people
 using this protocol, either one will not succeed or both will removed by
 use of KILL (4.6.1).

 9.2.2 Channels

 The current channel layout requires that all servers know about all
 channels, their inhabitants and properties. Besides not scaling well, the
 issue of privacy is also a concern. A collision of channels is treated as
 an inclusive event (both people who create the new channel are considered
 to be members of it) rather than an exclusive one such as used to solve
 nickname collisions.

 9.2.3 Servers

 Although the number of servers is usually small relative to the number of
 users and channels, they two currently required to be known globally,
 either each one separately or hidden behind a mask.

 9.3 Algorithms

 In some places within the server code, it has not been possible to avoid
 N^2 algorithms such as checking the channel list of a set of clients.

 In current server versions, there are no database consistency checks, each
 server assumes that a neighbouring server is correct. This opens the door
 to large problems if a connecting server is buggy or otherwise tries to
 introduce contradictions to the existing net.

 Currently, because of the lack of unique internal and global labels, there
 are a multitude of race conditions that exist. These race conditions
 generally arise from the problem of it taking time for messages to
 traverse and effect the IRC network. Even by changing to unique labels,
 there are problems with channel-related commands being disrupted.

 10. Current support and availability

            Mailing lists for IRC related discussion:

                 Future protocol: ircd-three-request@eff.org

                 General discussion: operlist-request@eff.org

            Software implemenations

                 cs.bu.edu:/irc

                 nic.funet.fi:/pub/irc

                 coombs.anu.edu.au:/pub/irc

            Newsgroup: alt.irc

 Security Considerations

 Security issues are discussed in sections 4.1, 4.1.1, 4.1.3, 5.5, and 7.

 12. Authors' Addresses

 Jarkko Oikarinen
 Tuirantie 17 as 9
 90500 OULU
 FINLAND

 Email: jto@tolsun.oulu.fi

 Darren Reed
 4 Pateman Street
 Watsonia, Victoria 3087
 Australia

 Email: avalon@coombs.anu.edu.au

 Oikarinen & Reed [Page 65]

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