A slave process is spawned by the game's main server process for delegating potentially time-consuming tasks. The communication between these two processes it typically some form of Unix pipe or socket.
PennMUSH and TinyMUX use the slave process to handle reverse-DNS lookups and Ident lookups for the purpose of identifying the connecting user. Depending on what information can be gleaned (and whether the MUSH server is running on Windows), this information is available to the Wizard-flagged staff on the wizard-WHO in one of several forms as follows:
Player Name On For Idle Room Cmds Host Prism1 0:26 57s #1269 2 127.0.0.1 Prism2 0:27 56s #1270 3 dnsname.com Prism3 0:28 55s #1271 4 COMPUTERNAME Prism4 0:29 54s #1272 5 email@example.com Prism5 0:30 53s #1273 6 firstname.lastname@example.org
PennMUSH calls its slave process info_slave, and uses it for both reverse-DNS lookups and Ident lookups. It limits itself to 5 simultaneous lookups. It does not provide an in-game command to restart the slave. However, if the process exits for some reason, it is detected and automatically restarted. info_slave is not supported on Windows. On that OS, lookups are done synchronously in the main process.
TinyMUX calls its slave process slave, and uses it for both reverse-DNS lookups and Ident lookups. Currently, the Unix version of TinyMUX's slave limits itself to 20 simultaneous lookups. If the slave terminates for some reason, @startslave can be used to start it again. The Win32 version of TinyMUX does not use a separate slave process. Instead, it relies on five background threads with the main game process to accomplish the same work.