+In addition, such a server should at least send the numeric 005 (ISUPPORT)
+to its peer, containing the following information. Syntax: <key>=<value>,
+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 <http://www.irc.org/tech_docs/005.html> 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