ngIRCd - Next Generation IRC Server (c)2001-2008 Alexander Barton, alex@barton.de, http://www.barton.de/ ngIRCd is free software and published under the terms of the GNU General Public License. -- Protocol.txt -- I. Compatibility ~~~~~~~~~~~~~~~~ The ngIRCd implements the Internet Relay Chat (IRC) protocol version 2.10 as defined in RFC ("request for comment") 1459 and 2810-2813. These (and probably further relevant RFCs) are listed in doc/RFC.txt. Unfortunately, even the "original" ircd doesn't follow these specifications in all details. But because the ngIRCd should be a fully compatible replacement for this server ("ircd") it tries to emulate these differences. If you don't like this behavior please ./configure the ngIRCd using the "--enable-strict-rfc" command line option. But keep in mind: not all IRC clients are compatible with a server configured that way, some can't even connect at all! Therefore this option usually isn't desired for "normal server operation". II. The IRC+ Protocol ~~~~~~~~~~~~~~~~~~~~~ Starting with version 0.5.0, the ngIRCd extends the original IRC protocol as defined in RFC 2810-2813. This enhanced protocol is named "IRC+". It is backwards compatible to the "plain" IRC protocol and will only be used by the ngIRCd if it detects that the peer supports it as well. The "PASS" command is used to detect the protocol and peer versions see RFC 2813 (section 4.1.1) and below. II.1 Register new server link Command: PASS Parameters: [] Used by: servers only (with these parameters) is the password for this new server link as defined in the server configuration which is sent to the peer or received from it. consists of two parts and is at least 4, at most 14 characters long: the first four bytes contain the IRC protocol version number, whereas the first two bytes represent the major version, the last two bytes the minor version (the string "0210" indicates version 2.10, e.g.). The following optional(!) 10 bytes contain an implementation-dependent version number. Servers supporting the IRC+ protocol as defined in this document provide the string "-IRC+" here. Example for : "0210-IRC+". consists of two parts separated with the character "|" and is at most 100 bytes long. The first part contains the name of the implementation (ngIRCd sets this to "ngircd", the original ircd to "IRC", e.g.). The second part is implementation-dependent and should only be parsed if the peer supports the IRC+ protocol as well. In this case the following syntax is used: "[:]". is an ASCII representation of the clear-text server version number, indicates the supported IRC+ protocol extensions (and may be empty!). The following are defined at the moment: - C: The server supports the CHANINFO command. - L: INVITE- and BAN-lists should be synchronized between servers: if the peer understands this flag, it will send "MODE +I" and "MODE +b" commands after the server link has been established. - H: The server supports the "enhanced server handshake", see section II.2 for a detailed description. - o: IRC operators are allowed to change channel- and channel-user-modes even if they aren't channel-operator of the affected channel. - S: The server supports the SERVICE command (on this link). - Z: Compressed server links are supported by the server. Example for a complete string: "ngircd|0.7.5:CZ". The optional parameter is used to propagate server options as defined in RFC 2813, section 4.1.1. II.2 Enhanced Server Handshake The "enhanced server handshake" is used when both servers support this IRC+ extension, which is indicated by the 'H' flag in the sent with the PASS command, see section II.1. It basically means, that after exchanging the PASS and SERVER commands the server is not registered in the network (as usual), but that IRC numerics are exchanged until the numeric 376 (ENDOFMOTD) is received. Afterwards the peer is registered in the network as with the regular IRC protocol. A server implementing the enhanced server handshake (and indicating this using 'H' in the ) MUST ignore all unknown numerics to it silently. In addition, such a server should at least send the numeric 005 (ISUPPORT) to its peer, containing the following information. Syntax: =, one token per IRC parameter. If the server has to send more than 12 token it must send separate ISUPPORT numerics (this is a limitation of the IRC protocol which allows at max 15 arguments per command). - NICKLEN: Maximum nickname length. Default: 9. - CASEMAPPING: Case mapping used for nick- and channel name comparing. Default: "ascii", the chars [a-z] are lowercase of [A-Z]. - PREFIX: List of channel modes a person can get and the respective prefix a channel or nickname will get in case the person has it. The order of the modes goes from most powerful to least powerful. Default: "(ov)@+" - CHANTYPES: Supported channel prefixes. Default: "#". - CHANMODES: List of channel modes for 4 types, separated by comma (","): Mode that adds or removes a nick or address to a list, mode that changes a setting (both have always has a parameter), mode that changes a setting and only has a parameter when set, and mode that changes a setting and never has a parameter. For example "bI,k,l,imnPst". - CHANLIMIT: Maximum number of channels allowed to join by channel prefix, for example "#:10". Please see for details. The information exchanged using ISUPPORT can be used to detect configuration incompatibilities (different maximum nick name length, for example) and therefore to disconnect the peer prior to registering it in the network. II.3 Exchange channel-modes, topics, and persistent channels Command: CHANINFO Parameters: + [] Used by: servers only CHANINFO is used by servers to inform each other about a channel: its modes, channel key, user limits and its topic. is optional. If the channel already exists on the server receiving the CHANINFO command, it only adopts the (or the ) if there are no modes (or topic) already set. It there are already values set the server ignores the corresponding parameter. If the channel doesn't exists at all it will be created. The parameter must be ignored if a channel has no key (the parameter doesn't list the "k" channel mode). In this case should contain "*" because the parameter is required by the CHANINFO syntax and therefore can't be omitted. The parameter must be ignored when a channel has no user limit (the parameter doesn't list the "l" channel mode). In this case should be "0".