DNS configuration on our domain

Kevin Darcy kcd at daimlerchrysler.com
Wed Sep 13 21:26:05 UTC 2006

Steve Ingraham wrote:
>> 	You need to ensure that the PTR and A records are
>> 	consistent and that they also match the name emitted
>> 	in the HELO/EHLO of the SMTP transaction.
>> 	You PTR and A records are not consistent.
> Forgive me for my ignorance but could you explain this a little further?
> What is meant by the records are not consistent?  What name are you
> referring to when talking about the HELO/EHLO of the SMTP transaction?
> My apologies for asking what I am sure are very basic questions but I am
> trying to learn about this while trying to manage a system that I have
> inherited, did not set up and that is causing me a great deal of
> problems (which I am sure may very well be caused by my lack of
> knowledge about DNS).
Hmmm... I thought Mark's lookup transcript(s) illustrated the problem 
fairly well. A reverse lookup of the address yields the 
two names mail.occa.state.ok.us and mymail.okcca.net, yet only one of 
those names (mymail.okcca.net) resolves to the address. 
The other name (mail.occa.state.ok.us) resolves to a different address 
( and thus raises an inconsistency.

Generally speaking it's bad form to have a reverse (in-addr.arpa) name resolve to multiple PTRs. It's even worse, though, when one or more of the names in those PTRs resolve to some other address.

								- Kevin

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