[PLUG] Spammer techniques question (fwd)

[Rich Shepard]

  I cannot answer this question, sent by a friend of mine. Anyone here know
the answer?

Thanks,

Rich

---------- Forwarded message ----------
Do you or any of your fellow PLUGgers know how a spammer could harvest
e-mail addressees right off my server? I have a couple addresses I set up a
while ago but have never used or published, yet some spammers seem to have
discovered them. Can they actually read the /etc/passwd file to get lists of
users? How else (assuming I haven't been totally hacked) could they get this
info? Or are these just lucky guesses? How can I tell them there's no one
really there and that they are wasting their valuable time?