> From the times I was using sendmail, I remember that in case when > forward/reverse DNS didn't match, sendmail logged something like
> unknown (reverse.dns.hostname) [ip.ad.dr.ess] Log? relay=hedefserver.com [2.56.152.122] (may be forged) Or are you talking about the Received: header? Received: from idsrv10.idefense.com (user242.idefense.com [63.117.254.242] (may be forged)) Received: $?sfrom $s $.$?_($?s$|from $.$_ $s Sender's host name. Set from the -p command line flag or by the SMTP server code (in which case it is set to the EHLO/HELO parameter). If someone really wants the details of this: doc/op/op.* in the sendmail distribution explains it. -- Note: I will most likely not reply to mails that - use HTML - top post - quote more than necessary