4. Message detailsOn the following pages are descriptions of each message recognized by the IRC server and client. All commands described in this section must be implemented by any server for this protocol. Where the reply ERR_NOSUCHSERVER is listed, it means that the <server> parameter could not be found. The server must not send any other replies after this for that command. The server to which a client is connected is required to parse the complete message, returning any appropriate errors. If the server encounters a fatal error while parsing a message, an error must be sent back to the client and the parsing terminated. A fatal error may be considered to be incorrect command, a destination which is otherwise unknown to the server (server, nick or channel names fit this category), not enough parameters or incorrect privileges. If a full set of parameters is presented, then each must be checked for validity and appropriate responses sent back to the client. In the case of messages which use parameter lists using the comma as an item separator, a reply must be sent for each item. In the examples below, some messages appear using the full format: :Name COMMAND parameter list Such examples represent a message from "Name" in transit between servers, where it is essential to include the name of the original sender of the message so remote servers may send back a reply along the correct path. Note that while COMMAND is always given in uppercase in this document, it may be in any case in protocol messages. Thus servers and clients must implement case-insensitive matching for command names. 4.1 Connection RegistrationThe commands described here are used to register a connection with an IRC server as either a user or a server as well as correctly disconnect. A "PASS" command is not required for either client or server connection to be registered. But, if provided, it must precede the SERVER message or the latter of the NICK/USER combination. It is strongly recommended that all server connections have a password in order to give some level of security to the actual connections. The recommended order for a client to register is as follows: Note, however, that the NICK and USER commands may be issued in either order. After a client has completed the connection registration process, the server will send a greeting, as detailed in Section 8.5. Until the connection is registered, the server must respond to any non-registration commands with ERR_NOTREGISTERED. If the client has not yet provided a nickname, '*' should be used in place of the nickname in the error message. 15-441 Note: Instead of the elaborate greeting specified in Section 8.5, you should send a "message of the day", using the RPL_MOTDSTART, RPL_MOTD, and RPL_ENDOFMOTD messages. You may choose whatever you desire as the text of the message. 4.1.1 Password message
The PASS command is used to set a 'connection password'. If a connection password will be used, it must be set before any attempt to register the connection is made. Currently this requires that clients send a PASS command before sending the NICK/USER combination and servers send a PASS command before any SERVER command. The password supplied must match the one contained in the C/N lines (for servers) or I lines (for clients). It is possible to send multiple PASS commands before registering but only the last one sent is used for verification and it may not be changed once registered. Numeric Replies:
On success, no response is given. Example: PASS secretpasswordhere 4.1.2 Nick message
NICK message is used to give user a nickname or change the previous one. The <hopcount> parameter is only used by servers to indicate how far away a nick is from its home server. A local connection has a hopcount of 0. If supplied by a client, it must be ignored. If a NICK message arrives at a server which already knows about an identical nickname for another client, a nickname collision occurs. As a result of a nickname collision, all instances of the nickname are removed from the server's database, and a KILL command is issued to remove the nickname from all other server's database. If the NICK message causing the collision was a nickname change, then the original (old) nick must be removed as well. If the server recieves, from a directly connected client, a NICK identical to one learned from another server, the server may issue an ERR_NICKCOLLISION to the local client, drop the NICK command, and not generate any kills. If the server receives, from a directly connected client, a NICK indentical to the NICK of an existing local local user, the server may issue an ERR_NICKNAMEINUSE to the local client, drop the NICK command, and not generate any kills. If the user is already registered, the server must inform other users of the change in nickname. To do this, the server echoes the user's command to all other users that are on any of the same channels as him. The server must include a prefix in the echoed command to identify the originator of the command. If the command is successful, and the user is not already registered, no response is generated by the server. Numeric Replies:
Examples: NICK Wiz ; Introducing new nick "Wiz". NICK Kilroy ; user changes nickname from WiZ to Kilroy :WiZ!someone@host.example.edu NICK Kilroy ; server notifies other users that WiZ changed his nickname to Kilroy.15-441 Note: You should handle duplicate nicknames using ERR_NICKNAMEINUSE as described above. Your server should not generate KILL messages. All nicknames are case-insensitive, e.g. Wiz and wiz are the same nicknames. 4.1.3 User message
The USER message is used at the beginning of connection to specify the username, hostname, servername and realname of a new user. It is also used in communication between servers to indicate new user arriving on IRC, since only after both USER and NICK have been received from a client does a user become registered. Between servers USER must to be prefixed with client's NICKname. Note that hostname and servername are normally ignored by the IRC server when the USER command comes from a directly connected client (for security reasons), but they are used in server to server communication. This means that a NICK must always be sent to a remote server when a new user is being introduced to the rest of the network before the accompanying USER is sent. It must be noted that realname parameter must be the last parameter, because it may contain space characters and must be prefixed with a colon (':') to make sure this is recognised as such. Since it is easy for a client to lie about its username by relying solely on the USER message, the use of an "Identity Server" is recommended. If the host which a user connects from has such a server enabled the username is set to that as in the reply from the "Identity Server". If the command is successful, no reply is generated Numeric Replies:
Examples: USER guest tolmoon tolsun :Ronnie Reagan ; User registering themselves with a username of "guest" and real name "Ronnie Reagan". :testnick USER guest tolmoon tolsun :Ronnie Reagan ; message between servers with the nickname for which the USER command belongs to 15-441 Note: As noted above, you should ignore the hostname specified by the client. You should obtain the hostname via reverse lookup, as mentioned in Section 1.2. 4.1.4 Server message
The server message is used to tell a server that the other end of a new connection is a server. This message is also used to pass server data over whole net. When a new server is connected to net, information about it be broadcast to the whole network. <hopcount> is used to give all servers some internal information on how far away all servers are. With a full server list, it would be possible to construct a map of the entire server tree, but hostmasks prevent this from being done. The SERVER message must only be accepted from either (a) a connection which is yet to be registered and is attempting to register as a server, or (b) an existing connection to another server, in which case the SERVER message is introducing a new server behind that server. Most errors that occur with the receipt of a SERVER command result in the connection being terminated by the destination host (target SERVER). Error replies are usually sent using the "ERROR" command rather than the numeric since the ERROR command has several useful properties which make it useful here. If a SERVER message is parsed and attempts to introduce a server which is already known to the receiving server, the connection from which that message must be closed (following the correct procedures), since a duplicate route to a server has formed and the acyclic nature of the IRC tree broken. Numeric Replies: Example: SERVER test.oulu.fi 1 :[tolsun.oulu.fi] Experimental server ; New server test.oulu.fi introducing itself and attempting to register. The name in []'s is the hostname for the host running test.oulu.fi. :tolsun.oulu.fi SERVER csd.bu.edu 5 :BU Central Server ; Server tolsun.oulu.fi is our uplink for csd.bu.edu which is 5 hops away. 4.1.5 Oper
OPER message is used by a normal user to obtain operator privileges. The combination of <user> and <password> are required to gain Operator privileges. If the client sending the OPER command supplies the correct password for the given user, the server then informs the rest of the network of the new operator by issuing a "MODE +o" for the clients nickname. The OPER message is client-server only. Numeric Replies:
Example: OPER foo bar ; Attempt to register as an operator using a username of "foo" and "bar" as the password. 4.1.6 Quit
A client session is ended with a quit message. The server must close the connection to a client which sends a QUIT message. If a "Quit Message" is given, this will be sent instead of the default message, the nickname. The server must inform other users of the client's departure by echoing the QUIT command to all users sharing channels with the departing client, in the same manner as for a nickname change. When netsplits (disconnecting of two servers) occur, the quit message is composed of the names of two servers involved, separated by a space. The first name is that of the server which is still connected and the second name is that of the server that has become disconnected. If, for some other reason, a client connection is closed without the client issuing a QUIT command (e.g. client dies and EOF occurs on socket), the server must still notify other users of the client's departure. The servers is required to fill in the quit message with some sort of message reflecting the nature of the event which caused the departure. Numeric Replies: Examples: QUIT :Gone to have lunch ; Preferred message format. :Kilroy!someone@host.example.edu QUIT :Connection closed ; server informing users that Kilroy closed his connection to the server 15-441 Note: As specified above, if a client session is ended, the server must notify other users of the client's departure (including a client connection ends abruptly) by sending a QUIT message with some explanation to all other users sharing the channel with the departing client. No message need to be sent if the client is not in any channel. 4.1.7 Server quit message
The SQUIT message is needed to tell about quitting or dead servers. If a server wishes to break the connection to another server it must send a SQUIT message to the other server, using the the name of the other server as the server parameter, which then closes its connection to the quitting server. This command is also available operators to help keep a network of IRC servers connected in an orderly fashion. Operators may also issue an SQUIT message for a remote server connection. In this case, the SQUIT must be parsed by each server inbetween the operator and the remote server, updating the view of the network held by each server as explained below. The <comment> should be supplied by all operators who execute a SQUIT for a remote server (that is not connected to the server they are currently on) so that other operators are aware for the reason of this action. The <comment> is also filled in by servers which may place an error or similar message here. Both of the servers which are on either side of the connection being closed are required to to send out a SQUIT message (to all its other server connections) for all other servers which are considered to be behind that link. Similarly, a QUIT message must be sent to the other connected servers rest of the network on behalf of all clients behind that link. In addition to this, all channel members of a channel which lost a member due to the split must be sent a QUIT message. If a server connection is terminated prematurely (e.g. the server on the other end of the link died), the server which detects this disconnection is required to inform the rest of the network that the connection has closed and fill in the comment field with something appropriate. Numeric replies:
Example: SQUIT tolsun.oulu.fi :Bad Link ? ; the server link tolson.oulu.fi has been terminated because of "Bad Link". :Trillian SQUIT cm22.eng.umd.edu :Server out of control ; message from Trillian to disconnect "cm22.eng.umd.edu" from the net because "Server out of control". 4.2 Channel operationsThis group of messages is concerned with manipulating channels, their properties (channel modes), and their contents (typically clients). In implementing these, a number of race conditions are inevitable when clients at opposing ends of a network send commands which will ultimately clash. It is also required that servers keep a nickname history to ensure that wherever a <nick> parameter is given, the server check its history in case it has recently been changed. 4.2.1 Join message
The JOIN command is used by client to start listening a specific channel. If the channel does not exist, it is created automatically. If the user is already on the channel, the message is silently ignored. Whether or not a client is allowed to join a channel is checked only by the server the client is connected to; all other servers automatically add the user to the channel when it is received from other servers. The conditions which affect this are as follows: These are discussed in more detail under the MODE command (see section 4.2.3 for more details). A server may limit the maximum number of channels to which a user can simultaneously subscribe. If the JOIN command would result in the user exceeding such a limit, the server must return ERR_TOOMANYCHANNELS. Once a user has joined a channel, they receive notice about all commands their server receives which affect the channel. This includes MODE, KICK, JOIN, PART, QUIT and of course PRIVMSG/NOTICE. The JOIN command needs to be broadcast to all servers so that each server knows where to find the users who are on the channel. This allows optimal delivery of PRIVMSG/NOTICE messages to the channel. If a JOIN is successful, the user is then sent the channel's topic, if set (using RPL_TOPIC) and the list of users who are on the channel (using RPL_NAMREPLY), which must include the user joining. The list of users is terminated with RPL_ENDOFNAMES. The JOIN command is echoed to all users on the channel, including the new user. This is repeated for each channel in the JOIN message. Numeric Replies:
Examples: JOIN #foobar ; join channel #foobar. JOIN &foo fubar ; join channel &foo using key "fubar". JOIN #foo,&bar fubar ; join channel #foo using key "fubar" and &bar using no key. JOIN #foo,#bar fubar,foobar ; join channel #foo using key "fubar". and channel #bar using key "foobar". JOIN #foo,#bar ; join channels #foo and #bar. :WiZ JOIN #Twilight_zone ; JOIN message from WiZ 15-441 Note: Instead of supporting a client to join multiple channels simultaneously, your server should restrict a client to be the member of at most one channel. Joining a new channel should implicitly causes the client to leave the current channel. In such case, to be compliant with standard IRC clients, your server should make up a QUIT message, which uses the QUIT format in this project (assuming it from the leaving client) (see Section 4.1.6) to echo to all other users on the old channel. 15-441 Note: We will ignore "key" parameters in the JOIN command. There will be no access restriction on the channels. We will also ignore channel masks in this project. 15-441 Note: If multiple channels are given by the user, your server should only JOIN the user to the first channel, and ignore the rest. 15-441 Note: Similar to nicknames, channel names are also case-insensitive. 4.2.2 Part message
The PART message causes the client sending the message to be removed from the list of active users for all given channels listed in the parameter string. If the parameters are valid, the server must echo the command to all users on the channel(s). This should be done before the parting user is removed from the channel. If the parting user is the only member of the channel, the server must delete the channel. Numeric Replies:
Examples: PART #twilight_zone ; leave channel "#twilight_zone" PART #oz-ops,&group5 ; leave both channels "&group5" and "#oz-ops". 15-441 Note: To reduce the number of unique responses you have to code,
PART will actually generate a QUIT response, of this form: 15-441 Note: If multiple channels are given by the user, the server should handle all of them, i.e. consider this message as separate PART messages. 4.2.3 Mode message
The MODE command is a dual-purpose command in IRC. It allows both usernames and channels to have their mode changed. The rationale for this choice is that one day nicknames will be obsolete and the equivalent property will be the channel. When parsing MODE messages, it is recommended that the entire message be parsed first and then the changes which resulted then passed on. 4.2.3.1 Channel modes
The MODE command is provided so that channel operators may change the characteristics of `their' channel. It is also required that servers be able to change channel modes so that channel operators may be created. The various modes available for channels are as follows:
When using the 'o' and 'b' options, a restriction on a total of three per mode command has been imposed. If only the channel parameter is specified, the server should return the current mode of the channel, using RPL_CHANNELMODEIS. Numeric Replies:
4.2.3.2 User modes
The user MODEs are typically changes which affect either how the client is seen by others or what 'extra' messages the client is sent. A user MODE command may only be accepted if both the sender of the message and the nickname given as a parameter are both the same. The available modes are as follows:
Additional modes may be available later on. If a user attempts to make themselves an operator using the "+o" flag, the attempt should be ignored. There is no restriction, however, on anyone `deopping' themselves (using "-o"). If only the channel parameter is specified, the server should return the current mode of the user, using RPL_UMODEIS. Numeric Replies:
Examples: Use of Channel Modes: MODE #Finnish +im ; Makes #Finnish channel moderated and 'invite-only'. MODE #Finnish +o Kilroy ; Gives 'chanop' privileges to Kilroy on channel #Finnish. MODE #Finnish +v Wiz ; Allow WiZ to speak on #Finnish. MODE #Fins -s ; Removes 'secret' flag from channel #Fins. MODE #42 +k oulu ; Set the channel key to "oulu". MODE #eu-opers +l 10 ; Set the limit for the number of users on channel to 10. MODE &oulu +b ; list ban masks set for channel. MODE &oulu +b *!*@* ; prevent all users from joining. MODE &oulu +b *!*@*.edu ; prevent any user from a hostname matching *.edu from joining. Use of user Modes: :MODE WiZ -w ; turns reception of WALLOPS messages off for WiZ. :Angel MODE Angel +i ; Message from Angel to make themselves invisible. MODE WiZ -o ; WiZ 'deopping' (removing operator status). The plain reverse of this command ("MODE WiZ +o") must not be allowed from users since would bypass the OPER command. 4.2.4 Topic message
The TOPIC message is used to change or view the topic of a channel. The topic for channel <channel> is returned if there is no <topic> given. If the <topic> parameter is present, the topic for that channel will be changed, if the channel modes permit this action. The server must inform current channel members of the topic change by echoing the command to all users currently on the channel. Numeric Replies:
Examples: :Wiz TOPIC #test :New topic ;User Wiz setting the topic. TOPIC #test :another topic ;set the topic on #test to "another topic". TOPIC #test ; check the topic for #test. 4.2.5 Names message
By using the NAMES command, a user can list all nicknames that are visible to them on any channel that they can see. Channel names which they can see are those which aren't private (+p) or secret (+s) or those which they are actually on. The <channel> parameter specifies which channel(s) to return information about if valid. There is no error reply for bad channel names. If no <channel> parameter is given, a list of all channels and their occupants is returned. At the end of this list, a list of users who are visible but either not on any channel or not on a visible channel are listed as being on `channel' "*". The response is returned using zero or more RPL_NAMREPLY messages. The response is terminated with the RPL_ENDOFNAMES message. Numeric Replies:
Examples: NAMES #twilight_zone,#42 ; list visible users on #twilight_zone and #42 if the channels are visible to you. NAMES ; list all visible channels and users 4.2.6 List message
The list message is used to list channels and their topics. If the <channel> parameter is used, only the status of that channel is displayed. Otherwise, list all channels. Private channels are listed (without their topics) as channel "Prv" unless the client generating the query is actually on that channel. Likewise, secret channels are not listed at all unless the client is a member of the channel in question. Regardless of the number of arguments in the message, the server generates only on reply block. Numeric Replies:
Examples: LIST ; List all channels. LIST #twilight_zone,#42 ; List channels #twilight_zone and #42 15-441 Note: We will ignore parameters in the LIST command. Your server should return information (channel name, number of users) about all existing channels. Channel topics can be omitted in the list reply. 4.2.7 Invite message
The INVITE message is used to invite users to a channel. The parameter <nickname> is the nickname of the person to be invited to the target channel <channel>. There is no requirement that the channel the target user is being invited to must exist or be a valid channel. To invite a user to a channel which is invite only (MODE +i), the client sending the invite must be recognised as being a channel operator on the given channel. The server must echo the INVITE message to the invited user. Numeric Replies:
Examples: :Angel INVITE Wiz #Dust ; User Angel inviting WiZ to channel #Dust INVITE Wiz #Twilight_Zone ; Command to invite WiZ to #Twilight_zone 4.2.8 Kick command
The KICK command can be used to forcibly remove a user from a channel. It 'kicks them out' of the channel (forced PART). Only a channel operator may kick another user out of a channel. Each server that receives a KICK message checks that it is valid (ie the sender is actually a channel operator) before removing the victim from the channel. Numeric Replies:
Examples: KICK &Melbourne Matthew ; Kick Matthew from &Melbourne KICK #Finnish John :Speaking English ; Kick John from #Finnish using "Speaking English" as the reason (comment). :WiZ KICK #Finnish John ; KICK message from WiZ to remove John from channel #Finnish NOTE: It is possible to extend the KICK command parameters to the following: <channel>{,<channel>} <user>{,<user>} [<comment>] 4.3 Server queries and commandsThe server query group of commands has been designed to return information about any server which is connected to the network. All servers connected must respond to these queries and respond correctly. Any invalid response (or lack thereof) must be considered a sign of a broken server and it must be disconnected/disabled as soon as possible until the situation is remedied. In these queries, where a parameter appears as "<server>", it will usually mean it can be a nickname or a server or a wildcard name of some sort. For each parameter, however, only one query and set of replies is to be generated. 4.3.1 Version message
The VERSION message is used to query the version of the server program. An optional parameter <server> is used to query the version of the server program which a client is not directly connected to. Numeric Replies:
Examples: :Wiz VERSION *.se ; message from Wiz to check the version of a server matching "*.se" VERSION tolsun.oulu.fi ; check the version of server "tolsun.oulu.fi". 4.3.2 Stats message
The stats message is used to query statistics of certain server. If <server> parameter is omitted, only the end of stats reply is sent back. The implementation of this command is highly dependent on the server which replies, although the server must be able to supply information as described by the queries below (or similar). A query may be given by any single letter which is only checked by the destination server (if given as the <server> parameter) and is otherwise passed on by intermediate servers, ignored and unaltered. The following queries are those found in the current IRC implementation and provide a large portion of the setup information for that server. Although these may not be supported in the same way by other versions, all servers should be able to supply a valid reply to a STATS query which is consistent with the reply formats currently used and the purpose of the query. The currently supported queries are:
Numeric Replies:
Examples: STATS m ; check the command usage for the server you are connected to :Wiz STATS c eff.org ; request by WiZ for C/N line information from server eff.org 4.3.3 Links message
With LINKS, a user can list all servers which are known by the server answering the query. The returned list of servers must match the mask, or if no mask is given, the full list is returned. If <remote server> is given in addition to <server mask>, the LINKS command is forwarded to the first server found that matches that name (if any), and that server is then required to answer the query. Numeric Replies:
Examples: LINKS *.au ; list all servers which have a name that matches *.au; :WiZ LINKS *.bu.edu *.edu ; LINKS message from WiZ to the first server matching *.edu for a list of servers matching *.bu.edu. 4.3.4 Time message
The time message is used to query local time from the specified server. If the server parameter is not given, the server handling the command must reply to the query. Numeric Replies:
Examples: TIME tolsun.oulu.fi ; check the time on the server "tolson.oulu.fi" Angel TIME *.au ; user angel checking the time on a server matching "*.au" 4.3.5 Connect message
The CONNECT command can be used to force a server to try to establish a new connection to another server immediately. CONNECT is a privileged command and is to be available only to IRC Operators. If a remote server is given then the CONNECT attempt is made by that server to <target server> and <port>. Numeric Replies:
Examples: CONNECT tolsun.oulu.fi ; Attempt to connect a server to tolsun.oulu.fi :WiZ CONNECT eff.org 6667 csd.bu.edu ; CONNECT attempt by WiZ to get servers eff.org and csd.bu.edu connected on port 6667. 4.3.6 Trace message
TRACE command is used to find the route to specific server. Each server that processes this message must tell the sender about it by sending a reply indicating it is a pass-through link, forming a chain of replies similar to that gained from using "traceroute". After sending this reply back, it must then send the TRACE message to the next server until given server is reached. If the <server> parameter is omitted, it is recommended that TRACE command send a message to the sender telling which servers the current server has direct connection to. If the destination given by "<server>" is an actual server, then the destination server is required to report all servers and users which are connected to it, although only operators are permitted to see users present. If the destination given by <server> is a nickname, they only a reply for that nickname is given. Numeric Replies: If the TRACE message is destined for another server, all intermediate servers must return a RPL_TRACELINK reply to indicate that the TRACE passed through it and where its going next. A TRACE reply may be composed of any number of the following numeric replies.
Examples: TRACE *.oulu.fi ; TRACE to a server matching *.oulu.fi :WiZ TRACE AngelDust ; TRACE issued by WiZ to nick AngelDust 4.3.7 Admin command
The admin message is used to find the name of the administrator of the given server, or current server if <server> parameter is omitted. Each server must have the ability to forward ADMIN messages to other servers. Numeric Replies:
Examples: ADMIN tolsun.oulu.fi ; request an ADMIN reply from tolsun.oulu.fi :WiZ ADMIN *.edu ; ADMIN request from WiZ for first server found to match *.edu. 4.3.8 Info command
The INFO command is required to return information which describes the server: its version, when it was compiled, the patchlevel, when it was started, and any other miscellaneous information which may be considered to be relevant. Numeric Replies:
Examples: INFO csd.bu.edu ; request an INFO reply from csd.bu.edu :Avalon INFO *.fi ; INFO request from Avalon for first server found to match *.fi. INFO Angel ; request info from the server that Angel is connected to. 4.4 Sending messagesThe main purpose of the IRC protocol is to provide a base for clients to communicate with each other. PRIVMSG and NOTICE are the only messages available which actually perform delivery of a text message from one client to another - the rest just make it possible and try to ensure it happens in a reliable and structured manner. 4.4.1 Private messages
PRIVMSG is used to send private messages between users. <target> is the nickname of the receiver of the message. <target> can also be a list of names or channels separated with commas. The <target> parameter may also me a host mask (#mask) or server mask ($mask). In both cases the server will only send the PRIVMSG to those who have a server or host matching the mask. The mask must have at least 1 (one) "." in it and no wildcards following the last ".". This requirement exists to prevent people sending messages to "#*" or "$*", which would broadcast to all users; from experience, this is abused more than used responsibly and properly. Wildcards are the '*' and '?' characters. This extension to the PRIVMSG command is only available to Operators. The message is delivered by sending a PRIVMSG with <text to be sent> to each of the targets. ONe ERR_NOSUCHNICK reply is generated for each <target> that does not match any nickname or channel. In the case where the target is a channel, the message is delivered to all users on the channel, except the originator of the message. The <target> is set to the channel name. Numeric Replies:
Examples: :Angel PRIVMSG Wiz :Hello are you receiving this message ? ; Message from Angel to Wiz. PRIVMSG Angel :yes I'm receiving it ! ; Message to Angel. PRIVMSG jto@tolsun.oulu.fi :Hello ! ; Message to a client on server tolsun.oulu.fi with username of "jto". PRIVMSG $*.fi :Server tolsun.oulu.fi rebooting. ; Message to everyone on a server which has a name matching *.fi. PRIVMSG #*.edu :NSFNet is undergoing work, expect interruptions ; Message to all users who come from a host which has a name matching *.edu. 15-441 Note: All targets will be either nicknames or channels. 15-441 Note: All channels are in -n mode, i.e. any registered user can send private messages to a channel. Also, private messages can be sent to another user not on the same channel. 15-441 Note: There is no limit on the number of targets. 4.4.2 Notice
The NOTICE message is used similarly to PRIVMSG. The difference between NOTICE and PRIVMSG is that automatic replies must never be sent in response to a NOTICE message. This rule applies to servers too - they must not send any error reply back to the client on receipt of a notice. The object of this rule is to avoid loops between a client automatically sending something in response to something it received. This is typically used by automatons (clients with either an AI or other interactive program controlling their actions) which are always seen to be replying lest they end up in a loop with another automaton. 4.5 User based queriesUser queries are a group of commands which are primarily concerned with finding details on a particular user or group users. When using wildcards with any of these commands, if they match, they will only return information on users who are 'visible' to you. The visibility of a user is determined as a combination of the user's mode and the common set of channels you are both on. 4.5.1 Who query
The WHO message is used by a client to generate a query which returns a list of information which 'matches' the <name> parameter given by the client. In the absence of the <name> parameter, all visible (users who aren't invisible (user mode +i) and who don't have a common channel with the requesting client) are listed. The same result can be achieved by using a <name> of "0" or any wildcard which will end up matching every entry possible. The <name> passed to WHO is matched against users' host, server, real name and nickname if the channel <name> cannot be found. If the channel <name> is found, WHO returns information about all the members of the channel. If the "o" parameter is passed only operators are returned according to the name mask supplied. The reply is returned with zero or more RPL_WHOREPLY messages, and terminated with a RPL_ENDOFWHO. Numeric Replies:
Examples: WHO *.fi ; List all users who match against "*.fi". WHO jto* o ; List all users with a match against "jto*" if they are an operator.
4.5.2 Whois query
This message is used to query information about particular user. The server will answer this message with several numeric messages indicating different statuses of each user which matches the nickmask (if you are entitled to see them). If no wildcard is present in the <nickmask>, any information about that nick which you are allowed to see is presented. A comma (',') separated list of nicknames may be given. The latter version sends the query to a specific server. It is useful if you want to know how long the user in question has been idle as only local server (ie. the server the user is directly connected to) knows that information, while everything else is globally known. A separate response (either ERR_NOSUCHNICK, or a set of RPL_WHOIS* messages) is generated for each <nickmask>. The responses are terminated with RPL_ENDOFWHOIS. Numeric Replies:
Examples: WHOIS wiz ; return available user information about nick WiZ WHOIS eff.org trillian ; ask server eff.org for user information about trillian 4.5.3 Whowas
Whowas asks for information about a nickname which no longer exists. This may either be due to a nickname change or the user leaving IRC. In response to this query, the server searches through its nickname history, looking for any nicks which are lexically the same (no wild card matching here). The history is searched backward, returning the most recent entry first. If there are multiple entries, up to <count> replies will be returned (or all of them if no <count> parameter is given). If a non-positive number is passed as being <count>, then a full search is done. Numeric Replies:
Examples: WHOWAS Wiz ; return all information in the nick history about nick "WiZ"; WHOWAS Mermaid 9 ; return at most, the 9 most recent entries in the nick history for "Mermaid"; WHOWAS Trillian 1 *.edu ; return the most recent history for "Trillian" from the first server found to match "*.edu". 4.6 Miscellaneous messagesMessages in this category do not fit into any of the above categories but are nonetheless still a part of and required by the protocol. 4.6.1 Kill message
The KILL message is used to cause a client-server connection to be closed by the server which has the actual connection. KILL is used by servers when they encounter a duplicate entry in the list of valid nicknames and is used to remove both entries. It is also available to operators. Clients which have automatic reconnect algorithms effectively make this command useless since the disconnection is only brief. It does however break the flow of data and can be used to stop large amounts of being abused, any user may elect to receive KILL messages generated for others to keep an 'eye' on would be trouble spots. In an arena where nicknames are required to be globally unique at all times, KILL messages are sent whenever 'duplicates' are detected (that is an attempt to register two users with the same nickname) in the hope that both of them will disappear and only 1 reappear. The comment given must reflect the actual reason for the KILL. For server-generated KILLs it usually is made up of details concerning the origins of the two conflicting nicknames. For users it is left up to them to provide an adequate reason to satisfy others who see it. To prevent/discourage fake KILLs from being generated to hide the identify of the KILLer, the comment also shows a 'kill-path' which is updated by each server it passes through, each prepending its name to the path. Numeric Replies:
KILL David (csd.bu.edu <- tolsun.oulu.fi) ; Nickname collision between csd.bu.edu and tolson.oulu.fi NOTE: It is recommended that only Operators be allowed to kill other users with KILL message. In an ideal world not even operators would need to do this and it would be left to servers to deal with. 4.6.2 Ping message
The PING message is used to test the presence of an active client at the other end of the connection. A PING message is sent at regular intervals if no other activity detected coming from a connection. If a connection fails to respond to a PING command within a set amount of time, that connection is closed. Any client which receives a PING message must respond to <server1> (server which sent the PING message out) as quickly as possible with an appropriate PONG message to indicate it is still there and alive. Servers should not respond to PING commands but rely on PINGs from the other end of the connection to indicate the connection is alive. If the <server2> parameter is specified, the PING message gets forwarded there. Numeric Replies:
Examples: PING tolsun.oulu.fi ; server sending a PING message to another server to indicate it is still alive. PING WiZ ; PING message being sent to nick WiZ 4.6.3 Pong message
PONG message is a reply to ping message. If parameter <daemon2> is given this message must be forwarded to given daemon. The <daemon> parameter is the name of the daemon who has responded to PING message and generated this message. Numeric Replies:
Examples: PONG csd.bu.edu tolsun.oulu.fi ; PONG message from csd.bu.edu to 4.6.4 Error
The ERROR command is for use by servers when reporting a serious or fatal error to its operators. It may also be sent from one server to another but must not be accepted from any normal unknown clients. An ERROR message is for use for reporting errors which occur with a server-to-server link only. An ERROR message is sent to the server at the other end (which sends it to all of its connected operators) and to all operators currently connected. It is not to be passed onto any other servers by a server if it is received from a server. When a server sends a received ERROR message to its operators, the message should be encapsulated inside a NOTICE message, indicating that the client was not responsible for the error. Numerics: 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.
|