A spanning tree of servers which clients connect to. At some point specified as RFC 1459 RFC 2812, modern-ish summary is recommended.
refer to RFCs or summary for commands and args,
of note: PRIVMSG is also used for channel messages,
not just user-user.
[:prefix] command params...<CRLF>
in descending level of privileges:
~ founder
& protected
@ operator
% halfop
+ voice