Warning - Reverse DNS does not match SMTP Banner

blackadder999
blackadder999 used Ask the Experts™
on
Hi

We have had a few emails not being delivered to users so I ran tests on the mxtoolbox site and got the following:

Warning - Reverse DNS does not match SMTP Banner

Can someone tell me if this likely to be causing an issue and how i go about resolving it?

Thanks
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Awarded 2009
Top Expert 2010

Commented:
In Exchange 2003 you need to change the FQDN in your SMTP Virtual Server

In 2007/2007 it's your send connector/receive connector.

the FQDN must match your rDNS record.
You may need to contact your ISP and have them setup reverse DNS for public IP address your mail server is using.  You could create a PTR record or rDNS.
http://en.wikipedia.org/wiki/Reverse_DNS_lookup
Hope this helps

Commented:
It will affect mail flow from the messaging systems that rlookup your Internet facing smtp server, how is your exchange sending/reciving mails from the Internet ?
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Author

Commented:
Sorry for the delay.  I've been checking today and  my reverse DNS is incorrect.   Is it just my ISP that I need to get to update this or is there something I need to do at the server end as well?

What do I get it set to - mail.mydomain.co.uk?

Thanks for all your help so far
Awarded 2009
Top Expert 2010
Commented:
Have a read through my blogpost here: http://demazter.wordpress.com/exchange-dns-configuration/

it explains everything

Author

Commented:
Thanks Demazter, that's explained it all and really helped me out.  I've made the changes and just waiting on my ISP now.

Thanks for all the advise.
Awarded 2009
Top Expert 2010

Commented:
You can also find my article published here on EE: http://www.experts-exchange.com/articles/Software/Server_Software/Email_Servers/Exchange/Exchange-DNS-Configuration.html
If you find the article useful please vote for it :-)

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