Given the following user:
Lamer120!lamer@184-83-202-75.ipt.aol.com
If you issue the command
/kickban Lamer120
The following server commands will be issued:
MODE #channel +b Lamer120!*@*
KICK #channel Lamer120
This is not a particularly effective banmask, as the user can simply change their nick (to, say, Lamer121, or Lamer120_) and rejoin the channel; some more ambitious idiots even have scripts that do this automatically. A much more effective mechanism is to ban the username and a subset of the hostname (a subset rather than the whole thing due to dynamic IP addresses that may change parts of the hostname periodically):
MODE #channel +b *!lamer@*.aol.com
KICK #channel Lamer120
The algorithm for masking is, obviously, to mask out the entire nickname and all but the last two fields of the hostname -- this may on occasion be overbroad, but will almost never be too narrow.
Note also that this banmask is what was called for in the original bug (http://colloquy.info/project/ticket/19) that called for the addition of the /kickban command.
