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 204.87.111.232 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 204.87.111.232 address. 
The other name (mail.occa.state.ok.us) resolves to a different address 
(204.87.111.225) 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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