Your department email address is always username@cs.umd.edu. Do not use hostnames in your email address, because in the event that that host is retired or is shut down for some reason, your mail will either get rejected, delayed, or lost somewhere in the system. username@cs.umd.edu is the address that will consistently get routed to you properly. This is contingent upon having your .forward files set up properly, of course. See showforwards, below.