MAIL FROM: <real.user@realdomain.com>

250 OK

RCPT TO: <bogus.user@bogusdomain.com>

250 OK

DATA
   From: real.user@realdomain.com
   To: bogus.user@bogusdomain.com
   Subj: I Can Relay Lots of Stuff Through You

   Tons and tons of text

250 OK

QUIT