/ZLINE [[!][+|-]<mask> [[<target>] <expiration> :<reason>]]

Sets (+), removes (-) or lists zlines (global ip bans). The target can either be
specified as * for a global zline (all servers) or a specific server can be
specified for a local zline confined to the specified server. The expiration
can be specified either in seconds or as a formatted time, eg 2d5m3s
(2 days 5 minutes 3 seconds. If the mask would not be permitted due
to it being too wide or affecting too many users, the "!" prefix may be
used to force the Z-line to be set anyway.

See Also: GLINE, SHUN
