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PTR Setting

Current DNS setting: (MX: abc.com) - Broadband Line 1
MX 10: mail1.abc.com
mail1.abc.com = (A Record and PTR) 192.168.0.1
 
Question 1:
We have added new broadband Line 2 for internet connection redundant. Line 2 will pick up the mail server sent out job if Line 1 is down.
For Broadband Line 2, what PTR setting is good for us?  

1. MX 20: mail1.abc.com
mail1.abc.com = (A Record and PTR) 10.10.10.1
OR
2. MX 20: mail2.abc.com
mail2.abc.com = (A Record and PTR) 10.10.10.1

Question 2:
For PTR checking, it is really check "domain name" or "A record"?


Thanks !
0
rhinoceros
Asked:
rhinoceros
2 Solutions
 
DipakCommented:
If you have a PTR record for your IP address, and the target of the PTR record has an "A record" pointing back to that same IP address, mail will not be rejected from your server due to an invalid PTR.

For more information go through below article.

http://forums.serverbeach.com/showthread.php?5469-Setting-up-PTR-s-%28aka-Reverse-DNS%29
0
 
b_levittCommented:
Unless your ISP is delegating the IP zone to you, you most likely need to request that either your ISP adds the PTR record or ask them to delegate to your dns so that you can do it.

I beleive dipak1383 is correct - the PTR record only needs to exist, it doesn't necessarily need to match anything.  That said, years ago some spam solutions were comparing the helo/ehlo smtp response from a sending server to it's ptr record for it's IP.  However, I believe that was against RFC recommendations.
0

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