RFC977 3.12.1.  SLAVE

   SLAVE

   Indicates to the server that this client connection is to a slave
   server, rather than a user.

   This command is intended for use in separating connections to single
   users from those to subsidiary ("slave") servers.  It may be used to
   indicate that priority should therefore be given to requests from
   this client, as it is presumably serving more than one person.  It
   might also be used to determine which connections to close when
   system load levels are exceeded, perhaps giving preference to slave
   servers.  The actual use this command is put to is entirely
   implementation dependent, and may vary from one host to another.  In
   NNTP servers which do not give priority to slave servers, this
   command must nonetheless be recognized and acknowledged.

RFC977 3.12.2.  Responses

   202 slave status noted