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

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

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.

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.

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.

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"

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 RFC1123 [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 )

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).

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.

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.

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.

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.

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.

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.

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.

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".

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".

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".

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.

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

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.

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

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

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

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

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.

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

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

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

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

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.

3.5 Service Query and Commands

The service query group of commands has been designed to return
information about any service which is connected to the network.

3.5.1 Servlist message

Command: SERVLIST
Parameters: [ <mask> [ <type> ] ]

The SERVLIST command is used to list services currently connected to
the network and visible to the user issuing the command. The
optional parameters may be used to restrict the result of the query
(to matching services names, and services type).

Numeric Replies:

RPL_SERVLIST RPL_SERVLISTEND

3.5.2 Squery

Command: SQUERY
Parameters: <servicename> <text>

The SQUERY command is used similarly to PRIVMSG. The only difference
is that the recipient MUST be a service. This is the only way for a
text message to be delivered to a service.

See PRIVMSG for more details on replies and example.

Examples:

SQUERY irchelp :HELP privmsg
; Message to the service with
nickname irchelp.

SQUERY dict@irc.fr :fr2en blaireau
; Message to the service with name
dict@irc.fr.

3.6 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.

Although services SHOULD NOT be using this class of message, they are
allowed to.

3.6.1 Who query

Command: WHO
Parameters: [ <mask> [ "o" ] ]

The WHO command is used by a client to generate a query which returns
a list of information which 'matches' the <mask> parameter given by
the client. In the absence of the <mask> 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 <mask> of "0" or any wildcard which
will end up matching every visible user.

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

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

Numeric Replies:

ERR_NOSUCHSERVER
RPL_WHOREPLY RPL_ENDOFWHO

Examples:

WHO *.fi ; Command to list all users who match
against "*.fi".

WHO jto* o ; Command to list all users with a
match against "jto*" if they are an
operator.

3.6.2 Whois query

Command: WHOIS
Parameters: [ <target> ] <mask> *( "," <mask> )

This command is used to query information about particular user.
The server will answer this command with several numeric messages
indicating different statuses of each user which matches the mask (if
you are entitled to see them). If no wildcard is present in the
<mask>, any information about that nick which you are allowed to see
is presented.

If the <target> parameter is specified, it 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 (i.e., the server the
user is directly connected to) knows that information, while
everything else is globally known.

Wildcards are allowed in the <target> parameter.

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

3.6.3 Whowas

Command: WHOWAS
Parameters: <nickname> *( "," <nickname> ) [ <count> [ <target> ] ]

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.

Wildcards are allowed in the <target> parameter.

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".

3.7 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.

3.7.1 Kill message

Command: KILL
Parameters: <nickname> <comment>

The KILL command is used to cause a client-server connection to be
closed by the server which has the actual connection. Servers
generate KILL messages on nickname collisions. It MAY also be
available available to users who have the operator status.

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 'flooding' from abusive users or accidents. Abusive users usually
don't care as they will reconnect promptly and resume their abusive
behaviour. To prevent this command from 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.

When a client is removed as the result of a KILL message, the server
SHOULD add the nickname to the list of unavailable nicknames in an
attempt to avoid clients to reuse this name immediately which is
usually the pattern of abusive behaviour often leading to useless
"KILL loops". See the "IRC Server Protocol" document [IRC-SERVER]
for more information on this procedure.

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

NOTE:
It is RECOMMENDED that only Operators be allowed to kill other users
with KILL command. This command has been the subject of many
controversies over the years, and along with the above
recommendation, it is also widely recognized that not even operators
should be allowed to kill users on remote servers.

3.7.2 Ping message

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

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

When a PING message is received, the appropriate PONG message MUST be
sent as reply to <server1> (server which sent the PING message out)
as soon as possible. If the <server2> parameter is specified, it
represents the target of the ping, and the message gets forwarded
there.

Numeric Replies:

ERR_NOORIGIN ERR_NOSUCHSERVER

Examples:

PING tolsun.oulu.fi ; Command to send a PING message to
server

PING WiZ tolsun.oulu.fi ; Command from WiZ to send a PING
message to server "tolsun.oulu.fi"

PING :irc.funet.fi ; Ping message sent by server
"irc.funet.fi"

3.7.3 Pong message

Command: PONG
Parameters: <server> [ <server2> ]

PONG message is a reply to ping message. If parameter <server2> is
given, this message MUST be forwarded to given target. The <server>
parameter is the name of the entity who has responded to PING message
and generated this message.

Numeric Replies:

ERR_NOORIGIN ERR_NOSUCHSERVER

Example:

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

3.7.4 Error

Command: ERROR
Parameters: <error message>

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

Only an ERROR message SHOULD be used for reporting errors which occur
with a server-to-server link. An ERROR message is sent to the server
at the other end (which reports it to appropriate local users and
logs) and to appropriate local users and logs. It is not to be
passed onto any other servers by a server if it is received from a
server.

The ERROR message is also used before terminating a client
connection.

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.

4. Optional features

This section describes OPTIONAL messages. They are not required in a
working server implementation of the protocol described herein. In
the absence of the feature, 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.

From this section, only the USERHOST and ISON messages are available
to services.

4.1 Away

Command: AWAY
Parameters: [ <text> ]

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

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

Because of its high cost (memory and bandwidth wise), the AWAY
message SHOULD only be used for client-server communication. A
server MAY choose to silently ignore AWAY messages received from
other servers. To update the away status of a client across servers,
the user mode 'a' SHOULD be used instead. (See Section 3.1.5)

Numeric Replies:

RPL_UNAWAY RPL_NOWAWAY

Example:

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

4.2 Rehash message

Command: REHASH
Parameters: None

The rehash command is an administrative command which can be used by
an operator to force the server to re-read and process its
configuration file.

Numeric Replies:

RPL_REHASHING ERR_NOPRIVILEGES

Example:

REHASH ; message from user with operator
status to server asking it to reread
its configuration file.

4.3 Die message

Command: DIE
Parameters: None

An operator can use the DIE command to shutdown the server. 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.

The DIE command MUST always be fully processed by the server to which
the sending client is connected and MUST NOT be passed onto other
connected servers.

Numeric Replies:

ERR_NOPRIVILEGES

Example:

DIE ; no parameters required.

4.4 Restart message

Command: RESTART
Parameters: None

An operator can use the restart command to force the server to
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 MUST NOT be passed onto
other connected servers.

Numeric Replies:

ERR_NOPRIVILEGES

Example:

RESTART ; no parameters required.

4.5 Summon message

Command: SUMMON
Parameters: <user> [ <target> [ <channel> ] ]

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.

Numeric Replies:

ERR_NORECIPIENT ERR_FILEERROR
ERR_NOLOGIN ERR_NOSUCHSERVER
ERR_SUMMONDISABLED 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.

4.6 Users

Command: USERS
Parameters: [ <target> ]

The USERS command returns a list of users logged into the server in a
format similar to the UNIX commands who(1), rusers(1) and finger(1).
If disabled, the correct numeric MUST be returned to indicate this.

Because of the security implications of such a command, it SHOULD be
disabled by default in server implementations. Enabling it SHOULD
require recompiling the server or some equivalent change rather than
simply toggling an option and restarting the server. The procedure
to enable this command SHOULD also include suitable large comments.

Numeric Replies:

ERR_NOSUCHSERVER ERR_FILEERROR
RPL_USERSSTART RPL_USERS
RPL_NOUSERS RPL_ENDOFUSERS
ERR_USERSDISABLED

Disabled Reply:

ERR_USERSDISABLED

Example:

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

4.7 Operwall message

Command: WALLOPS
Parameters: <Text to be sent>

The WALLOPS command is used to send a message to all currently
connected users who have set the 'w' user mode for themselves. (See
Section 3.1.5 "User modes").

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. Due to this, it is RECOMMENDED that the implementation of
WALLOPS allows and recognizes only servers as the originators of
WALLOPS.

Numeric Replies:

ERR_NEEDMOREPARAMS

Example:

:csd.bu.edu WALLOPS :Connect '*.uiuc.edu 6667' from Joshua ; WALLOPS
message from csd.bu.edu announcing a
CONNECT message it received from
Joshua and acted upon.

4.8 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

Example:

USERHOST Wiz Michael syrk ; USERHOST request for information on
nicks "Wiz", "Michael", and "syrk"

:ircd.stealth.net 302 yournick :syrk=+syrk@millennium.stealth.net
; Reply for user syrk

4.9 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) type of 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 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 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

Example:

ISON phone trillian WiZ jarlek Avalon Angel Monstah syrk
; Sample ISON request for 7 nicks.

5. Replies

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.

5.1 Command responses

Numerics in the range from 001 to 099 are used for client-server
connections only and should never travel between servers. Replies
generated in the response to commands are found in the range from 200
to 399.

001 RPL_WELCOME
"Welcome to the Internet Relay Network
<nick>!<user>@<host>"
002 RPL_YOURHOST
"Your host is <servername>, running version <ver>"
003 RPL_CREATED
"This server was created <date>"
004 RPL_MYINFO
"<servername> <version> <available user modes>
<available channel modes>"

- The server sends Replies 001 to 004 to a user upon
successful registration.

005 RPL_BOUNCE
"Try server <server name>, port <port number>"

- Sent by the server to a user to suggest an alternative
server. This is often used when the connection is
refused because the server is already full.

302 RPL_USERHOST
":*1<reply> *( " " <reply> )"

- Reply format used by USERHOST to list replies to
the query list. The reply string is composed as
follows:

reply = nickname [ "*" ] "=" ( "+" / "-" ) 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
":*1<nick> *( " " <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> " " )"

- 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
Obsolete. Not used.

322 RPL_LIST
"<channel> <# visible> :<topic>"
323 RPL_LISTEND
":End of LIST"

- Replies RPL_LIST, RPL_LISTEND mark the 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 end reply MUST be sent.

325 RPL_UNIQOPIS
"<channel> <nickname>"

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.

346 RPL_INVITELIST
"<channel> <invitemask>"
347 RPL_ENDOFINVITELIST
"<channel> :End of channel invite list"

- When listing the 'invitations masks' for a given channel,
a server is required to send the list back using the
RPL_INVITELIST and RPL_ENDOFINVITELIST messages. A
separate RPL_INVITELIST is sent for each active mask.
After the masks have been listed (or if none present) a
RPL_ENDOFINVITELIST MUST be sent.

348 RPL_EXCEPTLIST
"<channel> <exceptionmask>"
349 RPL_ENDOFEXCEPTLIST
"<channel> :End of channel exception list"

- When listing the 'exception masks' for a given channel,
a server is required to send the list back using the
RPL_EXCEPTLIST and RPL_ENDOFEXCEPTLIST messages. A
separate RPL_EXCEPTLIST is sent for each active mask.
After the masks have been listed (or if none present)
a RPL_ENDOFEXCEPTLIST MUST be sent.

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> )
- "@" is used for secret channels, "*" for private
channels, and "=" for others (public channels).

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> <banmask>"
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 banmask. After the
banmasks 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 MUST 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.

383 RPL_YOURESERVICE
"You are service <servicename>"

- Sent by the server to a service upon successful
registration.

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
":<username> <ttyline> <hostname>"
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> V<protocol version>
<link uptime in seconds> <backstream sendq>
<upstream sendq>"
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*!*>@<hostserver> V<protocol version>"
207 RPL_TRACESERVICE
"Service <class> <name> <type> <active type>"
208 RPL_TRACENEWTYPE
"<newtype> 0 <client name>"
209 RPL_TRACECLASS
"Class <class> <count>"
210 RPL_TRACERECONNECT
Unused.
261 RPL_TRACELOG
"File <logfile> <debug level>"
262 RPL_TRACEEND
"<server name> <version & debug level> :End of TRACE"

- The RPL_TRACE* are all returned by the server in
response to the TRACE message. How many are
returned is dependent on 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.
RPL_TRACEEND is sent to indicate the end of the list.

211 RPL_STATSLINKINFO
"<linkname> <sendq> <sent messages>
<sent Kbytes> <received messages>
<received Kbytes> <time open>"

- reports statistics on a connection. <linkname>
identifies the particular connection, <sendq> is
the amount of data that is queued and waiting to be
sent <sent messages> the number of messages sent,
and <sent Kbytes> the amount of data sent, in
Kbytes. <received messages> and <received Kbytes>
are the equivalent of <sent messages> and <sent
Kbytes> for received data, respectively. <time
open> indicates how long ago the connection was
opened, in seconds.

212 RPL_STATSCOMMANDS
"<command> <count> <byte count> <remote count>"

- reports statistics on commands usage.

219 RPL_ENDOFSTATS
"<stats letter> :End of STATS report"

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

- reports the server uptime.

243 RPL_STATSOLINE
"O <hostmask> * <name>"

- reports the allowed hosts from where user may become IRC
operators.

221 RPL_UMODEIS
"<user mode string>"

- To answer a query about a client's own mode,
RPL_UMODEIS is sent back.

234 RPL_SERVLIST
"<name> <server> <mask> <type> <hopcount> <info>"

235 RPL_SERVLISTEND
"<mask> <type> :End of service listing"

- When listing services in reply to a SERVLIST message,
a server is required to send the list back using the
RPL_SERVLIST and RPL_SERVLISTEND messages. A separate
RPL_SERVLIST is sent for each service. After the
services have been listed (or if none present) a
RPL_SERVLISTEND MUST be sent.

251 RPL_LUSERCLIENT
":There are <integer> users and <integer>
services 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 RPL_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 institution (RPL_ADMINLOC2)

and finally the administrative contact for the
server (an email address here is REQUIRED)
in RPL_ADMINEMAIL.

263 RPL_TRYAGAIN
"<command> :Please wait a while and try again."

- When a server drops a command without processing it,
it MUST use the reply RPL_TRYAGAIN to inform the
originating client.

5.2 Error Replies

Error replies are found in the range from 400 to 599.

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
does not 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 or where the user is
banned 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> :<error code> recipients. <abort message>"

- 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.

- Returned to a client which trying to send a
PRIVMSG/NOTICE to too many recipients.

- Returned to a client which is attempting to JOIN a safe
channel using the shortname when there are more than one
such channel.

408 ERR_NOSUCHSERVICE
"<service name> :No such service"

- Returned to a client which is attempting to send a SQUERY
to a service which does not exist.

409 ERR_NOORIGIN
":No origin specified"

- PING or PONG message missing the originator parameter.

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"
415 ERR_BADMASK
"<mask> :Bad Server/host mask"

- 412 - 415 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> :Erroneous nickname"

- Returned after receiving a NICK message which contains
characters which do not fall in the defined set. See
section 2.3.1 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 from <user>@<host>"

- Returned by a server to a client when it detects a
nickname collision (registered of a NICK that
already exists by another server).

437 ERR_UNAVAILRESOURCE
"<nick/channel> :Nick/channel is temporarily unavailable"

- Returned by a server to a user trying to join a channel
currently blocked by the channel delay mechanism.

- Returned by a server to a user trying to change nickname
when the desired nickname is blocked by the nick delay
mechanism.

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 affecting 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 doesn't 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
":Unauthorized command (already registered)"

- 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.

466 ERR_YOUWILLBEBANNED

- Sent by a server to a user to inform that access to the
server will soon be denied.

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 for <channel>"
473 ERR_INVITEONLYCHAN
"<channel> :Cannot join channel (+i)"
474 ERR_BANNEDFROMCHAN
"<channel> :Cannot join channel (+b)"
475 ERR_BADCHANNELKEY
"<channel> :Cannot join channel (+k)"
476 ERR_BADCHANMASK
"<channel> :Bad Channel Mask"
477 ERR_NOCHANMODES
"<channel> :Channel doesn't support modes"
478 ERR_BANLISTFULL
"<channel> <char> :Channel list is full"

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 can't 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.

484 ERR_RESTRICTED
":Your connection is restricted!"

- Sent by the server to a user upon connection to indicate
the restricted nature of the connection (user mode "+r").

485 ERR_UNIQOPPRIVSNEEDED
":You're not the original channel operator"

- Any MODE requiring "channel creator" privileges MUST
return this error if the client making the attempt is not
a chanop on the specified channel.

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
":Cannot change mode for other users"

- Error sent to any user trying to view or change the
user mode for a user other than themselves.

5.3 Reserved numerics

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

1. no longer in use;

2. reserved for future planned use;

3. in current use but are part of a non-generic 'feature' of
the current IRC server.

231 RPL_SERVICEINFO 232 RPL_ENDOFSERVICES
233 RPL_SERVICE
300 RPL_NONE 316 RPL_WHOISCHANOP
361 RPL_KILLDONE 362 RPL_CLOSING
363 RPL_CLOSEEND 373 RPL_INFOSTART
384 RPL_MYPORTIS

213 RPL_STATSCLINE 214 RPL_STATSNLINE
215 RPL_STATSILINE 216 RPL_STATSKLINE
217 RPL_STATSQLINE 218 RPL_STATSYLINE
240 RPL_STATSVLINE 241 RPL_STATSLLINE
244 RPL_STATSHLINE 244 RPL_STATSSLINE
246 RPL_STATSPING 247 RPL_STATSBLINE
250 RPL_STATSDLINE

492 ERR_NOSERVICEHOST

6. Current implementations

The IRC software, version 2.10 is the only complete implementation of
the IRC protocol (client and server). Because of the small amount of
changes in the client protocol since the publication of RFC1459
[IRC], implementations that follow it are likely to be compliant with
this protocol or to require a small amount of changes to reach
compliance.

7. Current problems

There are a number of recognized problems with the IRC Client
Protocol, and more generally with the IRC Server Protocol. In order
to preserve backward compatibility with old clients, this protocol
has almost not evolved since the publication of RFC1459 [IRC].

7.1 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, it's 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 a server KILL (See Section 3.7.1).

7.2 Limitation of wildcards

There is no way to escape the escape character "" (%x5C). While
this isn't usually a problem, it makes it impossible to form a mask
with a backslash character ("") preceding a wildcard.

7.3 Security considerations

Security issues related to this protocol are discussed in the "IRC
Server Protocol" [IRC-SERVER] as they are mostly an issue for the
server side of the connection.

8. Current support and availability

Mailing lists for IRC related discussion:
General discussion: ircd-users@irc.org
Protocol development: ircd-dev@irc.org

Software implementations:
FTP://ftp.irc.org/irc/server
ftp://ftp.funet.fi/pub/unix/irc
ftp://ftp.irc.org/irc/clients

Newsgroup: alt.irc

9. Acknowledgements

Parts of this document were copied from the RFC1459 [IRC] which
first formally documented the IRC Protocol. It has also benefited
from many rounds of review and comments. In particular, the
following people have made significant contributions to this
document:

Matthew Green, Michael Neumayer, Volker Paulsen, Kurt Roeckx, Vesa
Ruokonen, Magnus Tjernstrom, Stefan Zehl.

10. References

[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC2119, March 1997.

[ABNF] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC2234, November 1997.

[HNAME] Braden, R., "Requirements for Internet Hosts --
Application and Support", STD 3, RFC1123, October 1989.

[IRC] Oikarinen, J. & D. Reed, "Internet Relay Chat Protocol",
RFC1459, May 1993.

[IRC-ARCH] Kalt, C., "Internet Relay Chat: Architecture", RFC2810,
April 2000.

[IRC-CHAN] Kalt, C., "Internet Relay Chat: Channel Management", RFC
2811, April 2000.

[IRC-SERVER] Kalt, C., "Internet Relay Chat: Server Protocol", RFC
2813, April 2000.

11. Author's Address

Christophe Kalt
99 Teaneck Rd, Apt #117
Ridgefield Park, NJ 07660
USA

EMail: kalt@stealth.net

12. Full Copyright Statement

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

This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.

The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.

This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

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