Tech-invite3GPPspaceIETF RFCsSIP
929190898887868584838281807978777675747372717069686766656463626160595857565554535251504948474645444342414039383736353433323130292827262524232221201918171615141312111009080706050403020100
in Index   Prev   Next

RFC 2812

Internet Relay Chat: Client Protocol

Pages: 63
Informational
Errata
Updates:  1459
Part 1 of 2 – Pages 1 to 31
None   None   Next

Top   ToC   RFC2812 - Page 1
Network Working Group                                            C. Kalt
Request for Comments: 2812                                    April 2000
Updates: 1459
Category: Informational


                  Internet Relay Chat: Client Protocol

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

IESG NOTE:

   The IRC protocol itself enables several possibilities of transferring
   data between clients, and just like with other transfer mechanisms
   like email, the receiver of the data has to be careful about how the
   data is handled. For more information on security issues with the IRC
   protocol, see for example http://www.irchelp.org/irchelp/security/.

Abstract

The IRC (Internet Relay Chat) protocol is for use with text based conferencing; the simplest client being any socket program capable of connecting to the server. This document defines the Client Protocol, and assumes that the reader is familiar with the IRC Architecture [IRC-ARCH].

Table of Contents

1. Labels ..................................................... 3 1.1 Servers ................................................ 3 1.2 Clients ................................................ 3 1.2.1 Users ............................................. 4 1.2.1.1 Operators .................................... 4 1.2.2 Services .......................................... 4 1.3 Channels ............................................... 4 2. The IRC Client Specification ............................... 5 2.1 Overview ............................................... 5 2.2 Character codes ........................................ 5 2.3 Messages ............................................... 5
Top   ToC   RFC2812 - Page 2
         2.3.1  Message format in Augmented BNF ...................   6
      2.4  Numeric replies ........................................   8
      2.5  Wildcard expressions ...................................   9
   3.  Message Details ............................................   9
      3.1  Connection Registration ................................  10
         3.1.1  Password message ..................................  10
         3.1.2  Nick message ......................................  10
         3.1.3  User message ......................................  11
         3.1.4  Oper message ......................................  12
         3.1.5  User mode message .................................  12
         3.1.6  Service message ...................................  13
         3.1.7  Quit ..............................................  14
         3.1.8  Squit .............................................  15
      3.2  Channel operations .....................................  15
         3.2.1  Join message ......................................  16
         3.2.2  Part message ......................................  17
         3.2.3  Channel mode message ..............................  18
         3.2.4  Topic message .....................................  19
         3.2.5  Names message .....................................  20
         3.2.6  List message ......................................  21
         3.2.7  Invite message ....................................  21
         3.2.8  Kick command ......................................  22
      3.3  Sending messages .......................................  23
         3.3.1  Private messages ..................................  23
         3.3.2  Notice ............................................  24
      3.4  Server queries and commands ............................  25
         3.4.1  Motd message ......................................  25
         3.4.2  Lusers message ....................................  25
         3.4.3  Version message ...................................  26
         3.4.4  Stats message .....................................  26
         3.4.5  Links message .....................................  27
         3.4.6  Time message ......................................  28
         3.4.7  Connect message ...................................  28
         3.4.8  Trace message .....................................  29
         3.4.9  Admin command .....................................  30
         3.4.10 Info command ......................................  31
      3.5  Service Query and Commands .............................  31
         3.5.1  Servlist message ..................................  31
         3.5.2  Squery ............................................  32
      3.6  User based queries .....................................  32
         3.6.1  Who query .........................................  32
         3.6.2  Whois query .......................................  33
         3.6.3  Whowas ............................................  34
      3.7  Miscellaneous messages .................................  34
         3.7.1  Kill message ......................................  35
         3.7.2  Ping message ......................................  36
         3.7.3  Pong message ......................................  37
         3.7.4  Error .............................................  37
Top   ToC   RFC2812 - Page 3
   4.  Optional features ..........................................  38
      4.1  Away ...................................................  38
      4.2  Rehash message .........................................  39
      4.3  Die message ............................................  39
      4.4  Restart message ........................................  40
      4.5  Summon message .........................................  40
      4.6  Users ..................................................  41
      4.7  Operwall message .......................................  41
      4.8  Userhost message .......................................  42
      4.9  Ison message ...........................................  42
   5.  Replies ....................................................  43
      5.1  Command responses ......................................  43
      5.2  Error Replies ..........................................  53
      5.3  Reserved numerics ......................................  59
   6.  Current implementations ....................................  60
   7.  Current problems ...........................................  60
      7.1  Nicknames ..............................................  60
      7.2  Limitation of wildcards ................................  61
      7.3  Security considerations ................................  61
   8.  Current support and availability ...........................  61
   9.  Acknowledgements ...........................................  61
   10.  References ................................................  62
   11.  Author's Address ..........................................  62
   12.  Full Copyright Statement ..................................  63

1. Labels

This section defines the identifiers used for the various components of the IRC protocol.

1.1 Servers

Servers are uniquely identified by their name, which has a maximum length of sixty three (63) characters. See the protocol grammar rules (section 2.3.1) for what may and may not be used in a server name.

1.2 Clients

For each client all servers MUST have the following information: a netwide unique identifier (whose format depends on the type of client) and the server which introduced the client.
Top   ToC   RFC2812 - Page 4

1.2.1 Users

Each user is distinguished from other users by a unique nickname having a maximum length of nine (9) characters. See the protocol grammar rules (section 2.3.1) for what may and may not be used in a nickname. While the maximum length is limited to nine characters, clients SHOULD accept longer strings as they may become used in future evolutions of the protocol.
1.2.1.1 Operators
To allow a reasonable amount of order to be kept within the IRC network, a special class of users (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 often necessary. Operators SHOULD be able to perform basic network tasks such as disconnecting and reconnecting servers as needed. In recognition of this need, the protocol discussed herein provides for operators only to be able to perform such functions. See sections 3.1.8 (SQUIT) and 3.4.7 (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 very delicate since its abuse is both destructive and annoying, and its benefits close to inexistent. For further details on this type of action, see section 3.7.1 (KILL).

1.2.2 Services

Each service is distinguished from other services by a service name composed of a nickname and a server name. As for users, the nickname has a maximum length of nine (9) characters. See the protocol grammar rules (section 2.3.1) for what may and may not be used in a nickname.

1.3 Channels

Channels names are strings (beginning with a '&', '#', '+' or '!' character) of length up to fifty (50) characters. Apart from the requirement that the first character is either '&', '#', '+' or '!', the only restriction on a channel name is that it SHALL NOT contain any spaces (' '), a control G (^G or ASCII 7), a comma (','). Space is used as parameter separator and command is used as a list item separator by the protocol). A colon (':') can also be used as a delimiter for the channel mask. Channel names are case insensitive.
Top   ToC   RFC2812 - Page 5
   See the protocol grammar rules (section 2.3.1) for the exact syntax
   of a channel name.

   Each prefix characterizes a different channel type.  The definition
   of the channel types is not relevant to the client-server protocol
   and thus it is beyond the scope of this document.  More details can
   be found in "Internet Relay Chat: Channel Management" [IRC-CHAN].

2. The IRC Client Specification

2.1 Overview

The protocol as described herein is for use only with client to server connections when the client registers as a user.

2.2 Character codes

No specific character set is specified. The protocol is based on 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 US-ASCII terminal and a telnet connection. Because of IRC's Scandinavian 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 or channel names.

2.3 Messages

Servers and clients send each other 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 by nature. Each IRC message may consist of up to three main parts: the prefix (OPTIONAL), the command, and the command parameters (maximum of fifteen (15)). The prefix, command, and all parameters are separated by one ASCII space character (0x20) each.
Top   ToC   RFC2812 - Page 6
   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 from.  Clients SHOULD NOT use a prefix when sending a
   message; if they use one, the only valid prefix is the registered
   nickname associated with the client.

   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 of message lines.  See section 6 for more details about
   current implementations.

2.3.1 Message format in Augmented 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 (<params>). The Augmented BNF representation for this is: message = [ ":" prefix SPACE ] command [ params ] crlf prefix = servername / ( nickname [ [ "!" user ] "@" host ] ) command = 1*letter / 3digit params = *14( SPACE middle ) [ SPACE ":" trailing ] =/ 14( SPACE middle ) [ SPACE [ ":" ] trailing ] nospcrlfcl = %x01-09 / %x0B-0C / %x0E-1F / %x21-39 / %x3B-FF ; any octet except NUL, CR, LF, " " and ":" middle = nospcrlfcl *( ":" / nospcrlfcl ) trailing = *( ":" / " " / nospcrlfcl ) SPACE = %x20 ; space character crlf = %x0D %x0A ; "carriage return" "linefeed"
Top   ToC   RFC2812 - Page 7
   NOTES:
      1) 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 the parameter.

      2) The NUL (%x00) character is not special in message framing, and
         basically could end up inside a parameter, but it would cause
         extra complexities in normal C string handling. Therefore, NUL
         is not allowed within messages.

   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     =  nickname / server
  msgtarget  =  msgto *( "," msgto )
  msgto      =  channel / ( user [ "%" host ] "@" servername )
  msgto      =/ ( user "%" host ) / targetmask
  msgto      =/ nickname / ( nickname "!" user "@" host )
  channel    =  ( "#" / "+" / ( "!" channelid ) / "&" ) chanstring
                [ ":" chanstring ]
  servername =  hostname
  host       =  hostname / hostaddr
  hostname   =  shortname *( "." shortname )
  shortname  =  ( letter / digit ) *( letter / digit / "-" )
                *( letter / digit )
                  ; as specified in RFC 1123 [HNAME]
  hostaddr   =  ip4addr / ip6addr
  ip4addr    =  1*3digit "." 1*3digit "." 1*3digit "." 1*3digit
  ip6addr    =  1*hexdigit 7( ":" 1*hexdigit )
  ip6addr    =/ "0:0:0:0:0:" ( "0" / "FFFF" ) ":" ip4addr
  nickname   =  ( letter / special ) *8( letter / digit / special / "-" )
  targetmask =  ( "$" / "#" ) mask
                  ; see details on allowed masks in section 3.3.1
  chanstring =  %x01-07 / %x08-09 / %x0B-0C / %x0E-1F / %x21-2B
  chanstring =/ %x2D-39 / %x3B-FF
                  ; any octet except NUL, BELL, CR, LF, " ", "," and ":"
  channelid  = 5( %x41-5A / digit )   ; 5( A-Z / 0-9 )
Top   ToC   RFC2812 - Page 8
  Other parameter syntaxes are:

  user       =  1*( %x01-09 / %x0B-0C / %x0E-1F / %x21-3F / %x41-FF )
                  ; any octet except NUL, CR, LF, " " and "@"
  key        =  1*23( %x01-05 / %x07-08 / %x0C / %x0E-1F / %x21-7F )
                  ; any 7-bit US_ASCII character,
                  ; except NUL, CR, LF, FF, h/v TABs, and " "
  letter     =  %x41-5A / %x61-7A       ; A-Z / a-z
  digit      =  %x30-39                 ; 0-9
  hexdigit   =  digit / "A" / "B" / "C" / "D" / "E" / "F"
  special    =  %x5B-60 / %x7B-7D
                   ; "[", "]", "\", "`", "_", "^", "{", "|", "}"

  NOTES:
      1) The <hostaddr> syntax is given here for the sole purpose of
         indicating the format to follow for IP addresses.  This
         reflects the fact that the only available implementations of
         this protocol uses TCP/IP as underlying network protocol but is
         not meant to prevent other protocols to be used.

      2) <hostname> has a maximum length of 63 characters.  This is a
         limitation of the protocol as internet hostnames (in
         particular) can be longer.  Such restriction is necessary
         because IRC messages are limited to 512 characters in length.
         Clients connecting from a host which name is longer than 63
         characters are registered using the host (numeric) address
         instead of the host name.

      3) Some parameters used in the following sections of this
         documents are not defined here as there is nothing specific
         about them besides the name that is used for convenience.
         These parameters follow the general syntax defined for
         <params>.

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. 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 5 (Replies).
Top   ToC   RFC2812 - Page 9

2.5 Wildcard expressions

When wildcards are allowed in a string, it is referred as a "mask". For string matching purposes, the protocol allows the use of two special characters: '?' (%x3F) to match one and only one character, and '*' (%x2A) to match any number of any characters. These two characters can be escaped using the character '\' (%x5C). The Augmented BNF syntax for this is: mask = *( nowild / noesc wildone / noesc wildmany ) wildone = %x3F wildmany = %x2A nowild = %x01-29 / %x2B-3E / %x40-FF ; any octet except NUL, "*", "?" noesc = %x01-5B / %x5D-FF ; any octet except NUL and "\" matchone = %x01-FF ; matches wildone matchmany = *matchone ; matches wildmany Examples: a?c ; Matches any string of 3 characters in length starting with "a" and ending with "c" a*c ; Matches any string of at least 2 characters in length starting with "a" and ending with "c"

3. Message Details

On the following pages there 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 returned, it means that the target of the message could not be found. The server MUST NOT send any other replies after this error for that command. The server to which a client is connected is required to parse the complete message, and return any appropriate errors. If multiple parameters is presented, then each MUST be checked for validity and appropriate responses MUST be sent back to the client. In the case of incorrect messages which use parameter lists with comma as an item separator, a reply MUST be sent for each item.
Top   ToC   RFC2812 - Page 10

3.1 Connection Registration

The commands described here are used to register a connection with an IRC server as a user as well as to correctly disconnect. A "PASS" command is not required for a client connection to be registered, but it MUST precede the latter of the NICK/USER combination (for a user connection) or the SERVICE command (for a service connection). The RECOMMENDED order for a client to register is as follows: 1. Pass message 2. Nick message 2. Service message 3. User message Upon success, the client will receive an RPL_WELCOME (for users) or RPL_YOURESERVICE (for services) message indicating that the connection is now registered and known the to the entire IRC network. The reply message MUST contain the full client identifier upon which it was registered.

3.1.1 Password message

Command: PASS Parameters: <password> The PASS command is used to set a 'connection password'. The optional password can and MUST be set before any attempt to register the connection is made. Currently this requires that user send a PASS command before sending the NICK/USER combination. Numeric Replies: ERR_NEEDMOREPARAMS ERR_ALREADYREGISTRED Example: PASS secretpasswordhere

3.1.2 Nick message

Command: NICK Parameters: <nickname> NICK command is used to give user a nickname or change the existing one.
Top   ToC   RFC2812 - Page 11
   Numeric Replies:

           ERR_NONICKNAMEGIVEN             ERR_ERRONEUSNICKNAME
           ERR_NICKNAMEINUSE               ERR_NICKCOLLISION
           ERR_UNAVAILRESOURCE             ERR_RESTRICTED

   Examples:

   NICK Wiz                ; Introducing new nick "Wiz" if session is
                           still unregistered, or user changing his
                           nickname to "Wiz"

   :WiZ!jto@tolsun.oulu.fi NICK Kilroy
                           ; Server telling that WiZ changed his
                           nickname to Kilroy.

3.1.3 User message

Command: USER Parameters: <user> <mode> <unused> <realname> The USER command is used at the beginning of connection to specify the username, hostname and realname of a new user. The <mode> parameter should be a numeric, and can be used to automatically set user modes when registering with the server. This parameter is a bitmask, with only 2 bits having any signification: if the bit 2 is set, the user mode 'w' will be set and if the bit 3 is set, the user mode 'i' will be set. (See Section 3.1.5 "User Modes"). The <realname> may contain space characters. Numeric Replies: ERR_NEEDMOREPARAMS ERR_ALREADYREGISTRED Example: USER guest 0 * :Ronnie Reagan ; User registering themselves with a username of "guest" and real name "Ronnie Reagan". USER guest 8 * :Ronnie Reagan ; User registering themselves with a username of "guest" and real name "Ronnie Reagan", and asking to be set invisible.
Top   ToC   RFC2812 - Page 12

3.1.4 Oper message

Command: OPER Parameters: <name> <password> A normal user uses the OPER command to obtain operator privileges. The combination of <name> and <password> are REQUIRED to gain Operator privileges. Upon success, the user will receive a MODE message (see section 3.1.5) indicating the new user modes. 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.

3.1.5 User mode message

Command: MODE Parameters: <nickname> *( ( "+" / "-" ) *( "i" / "w" / "o" / "O" / "r" ) ) The user MODE's 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 MUST only be accepted if both the sender of the message and the nickname given as a parameter are both the same. If no other parameter is given, then the server will return the current settings for the nick. The available modes are as follows: a - user is flagged as away; i - marks a users as invisible; w - user receives wallops; r - restricted user connection; o - operator flag; O - local operator flag; s - marks a user for receipt of server notices. Additional modes may be available later on.
Top   ToC   RFC2812 - Page 13
   The flag 'a' SHALL NOT be toggled by the user using the MODE command,
   instead use of the AWAY command is REQUIRED.

   If a user attempts to make themselves an operator using the "+o" or
   "+O" flag, the attempt SHOULD be ignored as users could bypass the
   authentication mechanisms of the OPER command.  There is no
   restriction, however, on anyone `deopping' themselves (using "-o" or
   "-O").

   On the other hand, if a user attempts to make themselves unrestricted
   using the "-r" flag, the attempt SHOULD be ignored.  There is no
   restriction, however, on anyone `deopping' themselves (using "+r").
   This flag is typically set by the server upon connection for
   administrative reasons.  While the restrictions imposed are left up
   to the implementation, it is typical that a restricted user not be
   allowed to change nicknames, nor make use of the channel operator
   status on channels.

   The flag 's' is obsolete but MAY still be used.

   Numeric Replies:

           ERR_NEEDMOREPARAMS              ERR_USERSDONTMATCH
           ERR_UMODEUNKNOWNFLAG            RPL_UMODEIS

   Examples:

   MODE WiZ -w                     ; Command by WiZ to turn off
                                   reception of WALLOPS messages.

   MODE Angel +i                   ; Command from Angel to make herself
                                   invisible.

   MODE WiZ -o                     ; WiZ 'deopping' (removing operator
                                   status).

3.1.6 Service message

Command: SERVICE Parameters: <nickname> <reserved> <distribution> <type> <reserved> <info> The SERVICE command to register a new service. Command parameters specify the service nickname, distribution, type and info of a new service.
Top   ToC   RFC2812 - Page 14
   The <distribution> parameter is used to specify the visibility of a
   service.  The service may only be known to servers which have a name
   matching the distribution.  For a matching server to have knowledge
   of the service, the network path between that server and the server
   on which the service is connected MUST be composed of servers which
   names all match the mask.

   The <type> parameter is currently reserved for future usage.

   Numeric Replies:

           ERR_ALREADYREGISTRED            ERR_NEEDMOREPARAMS
           ERR_ERRONEUSNICKNAME
           RPL_YOURESERVICE                RPL_YOURHOST
           RPL_MYINFO

   Example:

   SERVICE dict * *.fr 0 0 :French Dictionary ; Service registering
                                   itself with a name of "dict".  This
                                   service will only be available on
                                   servers which name matches "*.fr".

3.1.7 Quit

Command: QUIT Parameters: [ <Quit Message> ] A client session is terminated with a quit message. The server acknowledges this by sending an ERROR message to the client. Numeric Replies: None. Example: QUIT :Gone to have lunch ; Preferred message format. :syrk!kalt@millennium.stealth.net QUIT :Gone to have lunch ; User syrk has quit IRC to have lunch.
Top   ToC   RFC2812 - Page 15

3.1.8 Squit

Command: SQUIT Parameters: <server> <comment> The SQUIT command is available only to operators. It is used to disconnect server links. Also servers can generate SQUIT messages on error conditions. A SQUIT message may also target a remote server connection. In this case, the SQUIT message will simply be sent to the remote server without affecting the servers in between the operator and the remote server. The <comment> SHOULD be supplied by all operators who execute a SQUIT for a remote server. The server ordered to disconnect its peer generates a WALLOPS message with <comment> included, so that other users may be aware of the reason of this action. Numeric replies: ERR_NOPRIVILEGES ERR_NOSUCHSERVER ERR_NEEDMOREPARAMS Examples: SQUIT tolsun.oulu.fi :Bad Link ? ; Command to uplink of the server tolson.oulu.fi to terminate its connection with comment "Bad Link". :Trillian SQUIT cm22.eng.umd.edu :Server out of control ; Command from Trillian from to disconnect "cm22.eng.umd.edu" from the net with comment "Server out of control".

3.2 Channel operations

This group of messages is concerned with manipulating channels, their properties (channel modes), and their contents (typically users). For this reason, these messages SHALL NOT be made available to services. All of these messages are requests which will or will not be granted by the server. The server MUST send a reply informing the user whether the request was granted, denied or generated an error. When the server grants the request, the message is typically sent back (eventually reformatted) to the user with the prefix set to the user itself.
Top   ToC   RFC2812 - Page 16
   The rules governing how channels are managed are enforced by the
   servers.  These rules are beyond the scope of this document.  More
   details are found in "Internet Relay Chat: Channel Management" [IRC-
   CHAN].

3.2.1 Join message

Command: JOIN Parameters: ( <channel> *( "," <channel> ) [ <key> *( "," <key> ) ] ) / "0" The JOIN command is used by a user to request to start listening to the specific channel. Servers MUST be able to parse arguments in the form of a list of target, but SHOULD NOT use lists when sending JOIN messages to clients. Once a user has joined a channel, he receives information about all commands his server receives affecting the channel. This includes JOIN, MODE, KICK, PART, QUIT and of course PRIVMSG/NOTICE. This allows channel members to keep track of the other channel members, as well as channel modes. If a JOIN is successful, the user receives a JOIN message as confirmation and 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. Note that this message accepts a special argument ("0"), which is a special request to leave all channels the user is currently a member of. The server will process this message as if the user had sent a PART command (See Section 3.2.2) for each channel he is a member of. Numeric Replies: ERR_NEEDMOREPARAMS ERR_BANNEDFROMCHAN ERR_INVITEONLYCHAN ERR_BADCHANNELKEY ERR_CHANNELISFULL ERR_BADCHANMASK ERR_NOSUCHCHANNEL ERR_TOOMANYCHANNELS ERR_TOOMANYTARGETS ERR_UNAVAILRESOURCE RPL_TOPIC Examples: JOIN #foobar ; Command to join channel #foobar. JOIN &foo fubar ; Command to join channel &foo using key "fubar".
Top   ToC   RFC2812 - Page 17
   JOIN #foo,&bar fubar            ; Command to join channel #foo using
                                   key "fubar" and &bar using no key.

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

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

   JOIN 0                          ; Leave all currently joined
                                   channels.

   :WiZ!jto@tolsun.oulu.fi JOIN #Twilight_zone ; JOIN message from WiZ
                                   on channel #Twilight_zone

3.2.2 Part message

Command: PART Parameters: <channel> *( "," <channel> ) [ <Part Message> ] The PART command causes the user sending the message to be removed from the list of active members for all given channels listed in the parameter string. If a "Part Message" is given, this will be sent instead of the default message, the nickname. This request is always granted by the server. Servers MUST be able to parse arguments in the form of a list of target, but SHOULD NOT use lists when sending PART messages to clients. Numeric Replies: ERR_NEEDMOREPARAMS ERR_NOSUCHCHANNEL ERR_NOTONCHANNEL Examples: PART #twilight_zone ; Command to leave channel "#twilight_zone" PART #oz-ops,&group5 ; Command to leave both channels "&group5" and "#oz-ops". :WiZ!jto@tolsun.oulu.fi PART #playzone :I lost ; User WiZ leaving channel "#playzone" with the message "I lost".
Top   ToC   RFC2812 - Page 18

3.2.3 Channel mode message

Command: MODE Parameters: <channel> *( ( "-" / "+" ) *<modes> *<modeparams> ) The MODE command is provided so that users may query and change the characteristics of a channel. For more details on available modes and their uses, see "Internet Relay Chat: Channel Management" [IRC- CHAN]. Note that there is a maximum limit of three (3) changes per command for modes that take a parameter. Numeric Replies: ERR_NEEDMOREPARAMS ERR_KEYSET ERR_NOCHANMODES ERR_CHANOPRIVSNEEDED ERR_USERNOTINCHANNEL ERR_UNKNOWNMODE RPL_CHANNELMODEIS RPL_BANLIST RPL_ENDOFBANLIST RPL_EXCEPTLIST RPL_ENDOFEXCEPTLIST RPL_INVITELIST RPL_ENDOFINVITELIST RPL_UNIQOPIS The following examples are given to help understanding the syntax of the MODE command, but refer to modes defined in "Internet Relay Chat: Channel Management" [IRC-CHAN]. Examples: MODE #Finnish +imI *!*@*.fi ; Command to make #Finnish channel moderated and 'invite-only' with user with a hostname matching *.fi automatically invited. MODE #Finnish +o Kilroy ; Command to give 'chanop' privileges to Kilroy on channel #Finnish. MODE #Finnish +v Wiz ; Command to allow WiZ to speak on #Finnish. MODE #Fins -s ; Command to remove 'secret' flag from channel #Fins. MODE #42 +k oulu ; Command to set the channel key to "oulu". MODE #42 -k oulu ; Command to remove the "oulu" channel key on channel "#42".
Top   ToC   RFC2812 - Page 19
   MODE #eu-opers +l 10            ; Command to set the limit for the
                                   number of users on channel
                                   "#eu-opers" to 10.

   :WiZ!jto@tolsun.oulu.fi MODE #eu-opers -l
                                   ; User "WiZ" removing the limit for
                                   the number of users on channel "#eu-
                                   opers".

   MODE &oulu +b                   ; Command to list ban masks set for
                                   the channel "&oulu".

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

   MODE &oulu +b *!*@*.edu +e *!*@*.bu.edu
                                   ; Command to prevent any user from a
                                   hostname matching *.edu from joining,
                                   except if matching *.bu.edu

   MODE #bu +be *!*@*.edu *!*@*.bu.edu
                                   ; Comment to prevent any user from a
                                   hostname matching *.edu from joining,
                                   except if matching *.bu.edu

   MODE #meditation e              ; Command to list exception masks set
                                   for the channel "#meditation".

   MODE #meditation I              ; Command to list invitations masks
                                   set for the channel "#meditation".

   MODE !12345ircd O               ; Command to ask who the channel
                                   creator for "!12345ircd" is

3.2.4 Topic message

Command: TOPIC Parameters: <channel> [ <topic> ] The TOPIC command 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 this action is allowed for the user requesting it. If the <topic> parameter is an empty string, the topic for that channel will be removed.
Top   ToC   RFC2812 - Page 20
   Numeric Replies:

           ERR_NEEDMOREPARAMS              ERR_NOTONCHANNEL
           RPL_NOTOPIC                     RPL_TOPIC
           ERR_CHANOPRIVSNEEDED            ERR_NOCHANMODES

   Examples:

   :WiZ!jto@tolsun.oulu.fi TOPIC #test :New topic ; User Wiz setting the
                                   topic.

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

   TOPIC #test :                   ; Command to clear the topic on
                                   #test.

   TOPIC #test                     ; Command to check the topic for
                                   #test.

3.2.5 Names message

Command: NAMES Parameters: [ <channel> *( "," <channel> ) [ <target> ] ] By using the NAMES command, a user can list all nicknames that are visible to him. For more details on what is visible and what is not, see "Internet Relay Chat: Channel Management" [IRC-CHAN]. The <channel> parameter specifies which channel(s) to return information about. 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' "*". If the <target> parameter is specified, the request is forwarded to that server which will generate the reply. Wildcards are allowed in the <target> parameter. Numerics: ERR_TOOMANYMATCHES ERR_NOSUCHSERVER RPL_NAMREPLY RPL_ENDOFNAMES
Top   ToC   RFC2812 - Page 21
   Examples:

   NAMES #twilight_zone,#42        ; Command to list visible users on
                                   #twilight_zone and #42

   NAMES                           ; Command to list all visible
                                   channels and users

3.2.6 List message

Command: LIST Parameters: [ <channel> *( "," <channel> ) [ <target> ] ] The list command is used to list channels and their topics. If the <channel> parameter is used, only the status of that channel is displayed. If the <target> parameter is specified, the request is forwarded to that server which will generate the reply. Wildcards are allowed in the <target> parameter. Numeric Replies: ERR_TOOMANYMATCHES ERR_NOSUCHSERVER RPL_LIST RPL_LISTEND Examples: LIST ; Command to list all channels. LIST #twilight_zone,#42 ; Command to list channels #twilight_zone and #42

3.2.7 Invite message

Command: INVITE Parameters: <nickname> <channel> The INVITE command is used to invite a user 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. However, if the channel exists, only members of the channel are allowed to invite other users. When the channel has invite-only flag set, only channel operators may issue INVITE command.
Top   ToC   RFC2812 - Page 22
   Only the user inviting and the user being invited will receive
   notification of the invitation.  Other channel members are not
   notified.  (This is unlike the MODE changes, and is occasionally the
   source of trouble for users.)

   Numeric Replies:

           ERR_NEEDMOREPARAMS              ERR_NOSUCHNICK
           ERR_NOTONCHANNEL                ERR_USERONCHANNEL
           ERR_CHANOPRIVSNEEDED
           RPL_INVITING                    RPL_AWAY

   Examples:

   :Angel!wings@irc.org INVITE Wiz #Dust

                                   ; Message to WiZ when he has been
                                   invited by user Angel to channel
                                   #Dust

   INVITE Wiz #Twilight_Zone       ; Command to invite WiZ to
                                   #Twilight_zone

3.2.8 Kick command

Command: KICK Parameters: <channel> *( "," <channel> ) <user> *( "," <user> ) [<comment>] The KICK command can be used to request the forced removal of a user from a channel. It causes the <user> to PART from the <channel> by force. For the message to be syntactically correct, there MUST be either one channel parameter and multiple user parameter, or as many channel parameters as there are user parameters. If a "comment" is given, this will be sent instead of the default message, the nickname of the user issuing the KICK. The server MUST NOT send KICK messages with multiple channels or users to clients. This is necessarily to maintain backward compatibility with old client software. Numeric Replies: ERR_NEEDMOREPARAMS ERR_NOSUCHCHANNEL ERR_BADCHANMASK ERR_CHANOPRIVSNEEDED ERR_USERNOTINCHANNEL ERR_NOTONCHANNEL
Top   ToC   RFC2812 - Page 23
   Examples:

   KICK &Melbourne Matthew         ; Command to kick Matthew from
                                   &Melbourne

   KICK #Finnish John :Speaking English
                                   ; Command to kick John from #Finnish
                                   using "Speaking English" as the
                                   reason (comment).

   :WiZ!jto@tolsun.oulu.fi KICK #Finnish John
                                   ; KICK message on channel #Finnish
                                   from WiZ to remove John from channel

3.3 Sending messages

The main purpose of the IRC protocol is to provide a base for clients to communicate with each other. PRIVMSG, NOTICE and SQUERY (described in Section 3.5 on Service Query and Commands) 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.

3.3.1 Private messages

Command: PRIVMSG Parameters: <msgtarget> <text to be sent> PRIVMSG is used to send private messages between users, as well as to send messages to channels. <msgtarget> is usually the nickname of the recipient of the message, or a channel name. The <msgtarget> parameter may also be 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. 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
Top   ToC   RFC2812 - Page 24
   Examples:

   :Angel!wings@irc.org PRIVMSG Wiz :Are you receiving this message ?
                                   ; Message from Angel to Wiz.

   PRIVMSG Angel :yes I'm receiving it !
                                   ; Command to send a message to Angel.

   PRIVMSG jto@tolsun.oulu.fi :Hello !
                                   ; Command to send a message to a user
                                   on server tolsun.oulu.fi with
                                   username of "jto".

   PRIVMSG kalt%millennium.stealth.net@irc.stealth.net :Are you a frog?
                                   ; Message to a user on server
                                   irc.stealth.net with username of
                                   "kalt", and connected from the host
                                   millennium.stealth.net.

   PRIVMSG kalt%millennium.stealth.net :Do you like cheese?
                                   ; Message to a user on the local
                                   server with username of "kalt", and
                                   connected from the host
                                   millennium.stealth.net.

   PRIVMSG Wiz!jto@tolsun.oulu.fi :Hello !
                                   ; Message to the user with nickname
                                   Wiz who is connected from the host
                                   tolsun.oulu.fi and has the username
                                   "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.

3.3.2 Notice

Command: NOTICE Parameters: <msgtarget> <text> The NOTICE command 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
Top   ToC   RFC2812 - Page 25
   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 clients automatically sending something in response to
   something it received.

   This command is available to services as well as users.

   This is typically used by services, and automatons (clients with
   either an AI or other interactive program controlling their actions).

   See PRIVMSG for more details on replies and examples.

3.4 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. In these queries, where a parameter appears as <target>, wildcard masks are usually valid. For each parameter, however, only one query and set of replies is to be generated. In most cases, if a nickname is given, it will mean the server to which the user is connected. These messages typically have little value for services, it is therefore RECOMMENDED to forbid services from using them.

3.4.1 Motd message

Command: MOTD Parameters: [ <target> ] The MOTD command is used to get the "Message Of The Day" of the given server, or current server if <target> is omitted. Wildcards are allowed in the <target> parameter. Numeric Replies: RPL_MOTDSTART RPL_MOTD RPL_ENDOFMOTD ERR_NOMOTD

3.4.2 Lusers message

Command: LUSERS Parameters: [ <mask> [ <target> ] ] The LUSERS command is used to get statistics about the size of the IRC network. If no parameter is given, the reply will be about the whole net. If a <mask> is specified, then the reply will only
Top   ToC   RFC2812 - Page 26
   concern the part of the network formed by the servers matching the
   mask.  Finally, if the <target> parameter is specified, the request
   is forwarded to that server which will generate the reply.

   Wildcards are allowed in the <target> parameter.

   Numeric Replies:

           RPL_LUSERCLIENT                 RPL_LUSEROP
           RPL_LUSERUNKOWN                 RPL_LUSERCHANNELS
           RPL_LUSERME                     ERR_NOSUCHSERVER

3.4.3 Version message

Command: VERSION Parameters: [ <target> ] The VERSION command is used to query the version of the server program. An optional parameter <target> is used to query the version of the server program which a client is not directly connected to. Wildcards are allowed in the <target> parameter. Numeric Replies: ERR_NOSUCHSERVER RPL_VERSION Examples: VERSION tolsun.oulu.fi ; Command to check the version of server "tolsun.oulu.fi".

3.4.4 Stats message

Command: STATS Parameters: [ <query> [ <target> ] ] The stats command is used to query statistics of certain server. If <query> parameter is omitted, only the end of stats reply is sent back. A query may be given for any single letter which is only checked by the destination server and is otherwise passed on by intermediate servers, ignored and unaltered. Wildcards are allowed in the <target> parameter.
Top   ToC   RFC2812 - Page 27
   Except for the ones below, the list of valid queries is
   implementation dependent.  The standard queries below SHOULD be
   supported by the 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 Kbytes and messages for
                each direction;
            m - returns the usage count for each of commands supported
                by the server; commands for which the usage count is
                zero MAY be omitted;
            o - returns a list of configured privileged users,
                operators;
            u - returns a string showing how long the server has been
                up.

   It is also RECOMMENDED that client and server access configuration be
   published this way.

   Numeric Replies:

           ERR_NOSUCHSERVER
           RPL_STATSLINKINFO                RPL_STATSUPTIME
           RPL_STATSCOMMANDS                RPL_STATSOLINE
           RPL_ENDOFSTATS

   Examples:

   STATS m                         ; Command to check the command usage
                                   for the server you are connected to

3.4.5 Links message

Command: LINKS Parameters: [ [ <remote server> ] <server mask> ] With LINKS, a user can list all servernames, 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
Top   ToC   RFC2812 - Page 28
   Examples:

   LINKS *.au                      ; Command to list all servers which
                                   have a name that matches *.au;

   LINKS *.edu *.bu.edu            ; Command to list servers matching
                                   *.bu.edu as seen by the first server
                                   matching *.edu.

3.4.6 Time message

Command: TIME Parameters: [ <target> ] The time command is used to query local time from the specified server. If the <target> parameter is not given, the server receiving the command must reply to the query. Wildcards are allowed in the <target> parameter. Numeric Replies: ERR_NOSUCHSERVER RPL_TIME Examples: TIME tolsun.oulu.fi ; check the time on the server "tolson.oulu.fi"

3.4.7 Connect message

Command: CONNECT Parameters: <target server> <port> [ <remote server> ] The CONNECT command can be used to request a server to try to establish a new connection to another server immediately. CONNECT is a privileged command and SHOULD be available only to IRC Operators. If a <remote server> is given and its mask doesn't match name of the parsing server, the CONNECT attempt is sent to the first match of remote server. Otherwise the CONNECT attempt is made by the server processing the request. The server receiving a remote CONNECT command SHOULD generate a WALLOPS message describing the source and target of the request. Numeric Replies: ERR_NOSUCHSERVER ERR_NOPRIVILEGES ERR_NEEDMOREPARAMS
Top   ToC   RFC2812 - Page 29
   Examples:

   CONNECT tolsun.oulu.fi 6667     ; Command to attempt to connect local
                                   server to tolsun.oulu.fi on port 6667

3.4.8 Trace message

Command: TRACE Parameters: [ <target> ] TRACE command is used to find the route to specific server and information about its peers. Each server that processes this command MUST report to the sender about it. The replies from pass-through links form a chain, which shows route to destination. After sending this reply back, the query MUST be sent to the next server until given <target> server is reached. 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. After sending this reply back, it MUST then send the TRACE message to the next server until given server is reached. If the <target> parameter is omitted, it is RECOMMENDED that TRACE command sends a message to the sender telling which servers the local server has direct connection to. If the destination given by <target> is an actual server, the destination server is REQUIRED to report all servers, services and operators which are connected to it; if the command was issued by an operator, the server MAY also report all users which are connected to it. If the destination given by <target> is a nickname, then only a reply for that nickname is given. If the <target> parameter is omitted, it is RECOMMENDED that the TRACE command is parsed as targeted to the processing server. Wildcards are allowed in the <target> parameter. 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 it is going next. RPL_TRACELINK
Top   ToC   RFC2812 - Page 30
      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                RPL_TRACELOG
           RPL_TRACEEND

   Examples:

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

3.4.9 Admin command

Command: ADMIN Parameters: [ <target> ] The admin command is used to find information about the administrator of the given server, or current server if <target> parameter is omitted. Each server MUST have the ability to forward ADMIN messages to other servers. Wildcards are allowed in the <target> parameter. 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 ADMIN syrk ; ADMIN request for the server to which the user syrk is connected
Top   ToC   RFC2812 - Page 31

3.4.10 Info command

Command: INFO Parameters: [ <target> ] The INFO command is REQUIRED to return information describing 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. Wildcards are allowed in the <target> parameter. Numeric Replies: ERR_NOSUCHSERVER RPL_INFO RPL_ENDOFINFO Examples: INFO csd.bu.edu ; request an INFO reply from csd.bu.edu INFO Angel ; request info from the server that Angel is connected to.


(page 31 continued on part 2)

Next Section