Ioquake3 game engine (dedicated server)
/usr/lib/ioquake3/ioq3ded [+set option value]...
ioquake3-server is the dedicated server for the ioQuake3 game engine.
The version provided in Debian is not usually useful to run directly, and is not included in the PATH. The openarena and quake3 Debian packages provide wrapper scripts to launch servers for particular games.
Any console command can be prefixed with + and used as a command-line option (run the server in a terminal to use the console). The +set command is generally the most useful to use on the command line, but things like +map also work.
Options that can be set with +set (note that this is not a full list!) include:
g_banIPs <IP address>
net_ip <IP adress>
sv_maxPing <value> (Measurd in milliseconds)
sv_minPing <value> (Measurd in milliseconds)
timelimit <value> (Measured in minutes)