Newbie questions two.

[Mark on GCI Server]

Hey all,
  Where exactly does the qpopper pull the domain name information. Does it
pull from active zones in the DNS, or from the setup of sendmail? Currently,
the domain name on my mail server includes the hostname, and I don't want
the hostname in the mail addresses that I set up for my users. Any help
would be greatly appreciated.

Thanks,
Mark