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RFC 2812

Internet Relay Chat: Client Protocol

Pages: 63
Updates:  1459
Part 2 of 2 – Pages 31 to 63
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Top   ToC   RFC2812 - Page 31   prevText

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
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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 :fr2en blaireau ; Message to the service with name

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

   Numeric Replies:

           RPL_WHOREPLY                  RPL_ENDOFWHO


   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

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
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   WHOIS wiz                       ; return available user information
                                   about nick WiZ

   WHOIS trillian          ; ask server 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.
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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
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   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 ; Command to send a PING message to server PING WiZ ; Command from WiZ to send a PING message to server "" PING ; Ping message sent by server ""
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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 ; PONG message from to

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.
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   ERROR :Server *.fi already exists ; ERROR message to the other server
                                   which caused this error.

   NOTICE WiZ :ERROR from -- 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
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   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.
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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
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   SUMMON jto                      ; summon user jto on the server's

   SUMMON jto       ; summon user jto on the host which a
                                   server named "" is

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 ; request a list of users logged in on server

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").
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   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

   Numeric Replies:


   Example: WALLOPS :Connect '* 6667' from Joshua ; WALLOPS
                                   message from 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" 302 yournick ; 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
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   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

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

   Numeric Replies:

           RPL_ISON                      ERR_NEEDMOREPARAMS


   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.
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       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

           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

       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>"
              "<nick> :is an IRC operator"
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       317    RPL_WHOISIDLE
              "<nick> <integer> :seconds idle"
       318    RPL_ENDOFWHOIS
              "<nick> :End of WHOIS list"
              "<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.
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       325    RPL_UNIQOPIS
              "<channel> <nickname>"

              "<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

       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>"
              "<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
           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>"
              "<channel> :End of channel exception list"
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         - When listing the 'exception masks' for a given channel,
           a server is required to send the list back using the
           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
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           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
       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

       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
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           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

       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
           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
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       200    RPL_TRACELINK
              "Link <version & debug level> <destination>
               <next server> V<protocol version>
               <link uptime in seconds> <backstream sendq>
               <upstream sendq>"
              "Try. <class> <server>"
              "H.S. <class> <server>"
       203    RPL_TRACEUNKNOWN
              "???? <class> [<client IP address in dot form>]"
              "Oper <class> <nick>"
       205    RPL_TRACEUSER
              "User <class> <nick>"
       206    RPL_TRACESERVER
              "Serv <class> <int>S <int>C <server>
               <nick!user|*!*>@<host|server> 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>"
       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.
           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.
Top   ToC   RFC2812 - Page 51
           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.

              "<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.

              "<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

       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>"
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       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)"
              "<integer> :channels formed"
       255    RPL_LUSERME
              ":I have <integer> clients and <integer>

         - In processing an LUSERS message, the server
           sends a set of replies from RPL_LUSERCLIENT,
           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)
Top   ToC   RFC2812 - Page 53
           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.
Top   ToC   RFC2812 - Page 54
              "<nickname> :There was no such nickname"

         - Returned by WHOWAS to indicate there is no history
           information for that nickname.

              "<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.

              "<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.
Top   ToC   RFC2812 - Page 55
              "<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

       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.

              ":No nickname given"

         - Returned when a nickname parameter expected for a
           command and isn't found.

              "<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.

              "<nick> :Nickname is already in use"

         - Returned when a NICK message is processed that results
           in an attempt to change to a currently existing
Top   ToC   RFC2812 - Page 56
              "<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).

              "<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

              "<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.

              "<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.
Top   ToC   RFC2812 - Page 57
              ":SUMMON has been disabled"

         - Returned as a response to the SUMMON command.  MUST be
           returned by any server which doesn't implement it.

              ":USERS has been disabled"

         - Returned as a response to the USERS command.  MUST be
           returned by any server which does not implement it.

              ":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.

              "<command> :Not enough parameters"

         - Returned by the server by numerous commands to
           indicate to the client that it didn't supply enough

              ":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).

              ":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.

              ":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.
Top   ToC   RFC2812 - Page 58
              ":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.


         - 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"
              "<channel> :Cannot join channel (+l)"
       472    ERR_UNKNOWNMODE
              "<char> :is unknown mode char to me for <channel>"
              "<channel> :Cannot join channel (+i)"
              "<channel> :Cannot join channel (+b)"
              "<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

              "<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
Top   ToC   RFC2812 - Page 59
              ":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").

              ":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

              ":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.

              ":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;
Top   ToC   RFC2812 - Page 60
   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 RFC 1459 [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 RFC 1459 [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).
Top   ToC   RFC2812 - Page 61

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: Protocol development: Software implementations: Newsgroup: alt.irc

9. Acknowledgements

Parts of this document were copied from the RFC 1459 [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.
Top   ToC   RFC2812 - Page 62

10. References

[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [ABNF] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, November 1997. [HNAME] Braden, R., "Requirements for Internet Hosts -- Application and Support", STD 3, RFC 1123, October 1989. [IRC] Oikarinen, J. & D. Reed, "Internet Relay Chat Protocol", RFC 1459, May 1993. [IRC-ARCH] Kalt, C., "Internet Relay Chat: Architecture", RFC 2810, 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:
Top   ToC   RFC2812 - Page 63

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 Funding for the RFC Editor function is currently provided by the Internet Society.