It appears that the setting “Verify Connecting Hostname in DNS” does not work–it does not verify the connecting hostname. We set this attempting to pass a security scan–our ISS scanner tells us that our “SMTP server allows fake hostnames in HELO”. Sp we tried to fix.
Indeed, after setting this and rebooting the server, I can telnet to port 25 on the server, type in HELO dude, and it says, “Hello dude, pleased to meet you”. Exact transcript is below, with altered DNS and IP.
220 myserver.com ESMTP Service (Lotus Domino Release 8.5.1FP2) rea
dy at Wed, 8 Sep 2010 17:48:35 -0400
helo dude
250 myserver.com Hello dude ([111.11.111.11]), pleased to meet you