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Exchange DNS Problems

Posted on 2011-09-21
Medium Priority
Last Modified: 2012-06-21
I have an Exchange 2007 server trying to send mail to one particular domain and it keeps getting rejected saying there is an invalid PTR record..  here is the exact error message..

"mail.premier-technologies.net #501 Connecting IP must have valid PTR record for xx.xx.xx.xx ##"

Now, i have checked on MXToolbox for various checks..
*My MX record points to .. mail.domain. com as my proper public IP address
*I do a reverse lookup on that public IP address and i produce a PTR record that shows my public IP address in reverse order
I have an A record that points to my webmail.domain.com

Do I also need to have an A record created that points  mail.domain.com to my public IP?

I'm at a loss as to why this one domain is rejecting emails from my domain with invalid PRT record error message
Question by:ddsvi
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LVL 23

Expert Comment

ID: 36573964
go to www.mxtoolbox.com and run the diagnostics option.

If your mx record is mail.domain.com which points to, then the PTR record needs to point to mail.domain.com :)


Author Comment

ID: 36574027
The diagnostics shows Reverse DNS as Failed...  here are the resutls when I do a reverse lookup on my public IP address that is found from the MX lookup.

ptr:1x.5x.8x.2x <correct public IP>

Auth - N

Type - CNAME

Domain Name - 2x.8x.5x.1x.in-addr.arpa  <correct public IP>

Canonical Name - 26.24/2x.8x.5x.1x.in-addr.arpa <correct public IP>

TTL - 23 hrs

So please forgive me here.. but is this PTR record wrong?  Where should mail.domain.com be in the pointer record per your suggestion?
LVL 23

Accepted Solution

jakethecatuk earned 1000 total points
ID: 36574089
the PTR record is wrong.

you need to get your ISP to update it for you.

on MXToolbox, if you run the same test for Experts Exchange (http://mxtoolbox.com/SuperTool.aspx?action=mx%3aexperts-exchange.com), you will see that the IP address resolves back to mail.experts-exchange.com

Similarly, simple NSLOOKUP produces a similar result: -

> server
Default Server:  google-public-dns-a.google.com

> mail.experts-exchange.com
Server:  google-public-dns-a.google.com

Non-authoritative answer:
Name:    mail.dw.redsrci.com
Aliases:  mail.experts-exchange.com

Server:  google-public-dns-a.google.com

Name:    mail.experts-exchange.com


Does that make sense now?


Author Comment

ID: 36574134
That helps .. thank you very much!

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