reverse DNS does not match SMTP banner
Posted on 2015-01-14
Whilst carrying out some routine diagnostic work for our Microsoft Windows 2012 server running Exchange 2010, I was running MXTOOLBOX.com which produced the following results :-
SMTP Reverse DNS Mismatch
Warning - Reverse DNS does not match SMTP Banner
SMTP Transaction Time
8.315 seconds - Not good! on Transaction Time
SMTP Banner Check
OK - xxx.30.36.xx resolves to autodiscover.domainname.co.uk
OK - Supports TLS.
SMTP Connection Time
0.905 seconds - Good on Connection time
I am a little confused about what our reverse DNS should point to??
Our smtp mail service is configured as mail.domainname.co.uk
We also have an A host record pointing to autodiscover.domainname.co.uk
The SMTP banner is reorted by MXTOOLBOX as being autodiscover.domainname.co.uk
Do I get our host to set our reverse DNS to resolve to mail.domainname.co.uk ie our standard smtp or do I need it set to autodiscover.domainname.co.uk which is what the MXTOOLBOX.COM says our SMTP banner resolves to??
Any advisw would be much appreciated.
SMTP Open Relay
OK - Not an open relay.