You suspect that you are receiving messages with a forged From: address. What could help you find out where the mail is originating?
A.
Install TCP wrappers, and log all connections on port 25
B.
A dd the command ‘FR-strlog’ to the sendmail.cf file
C.
Add the command ‘define (‘LOG_REAL_FROM’) dnl’ to the sendmail.mc file
D.
Run a filter in the aliases file that checks the originating address when mail arrives
E.
Look in the Received: and Message-ID: parts of the mail header