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Community Member

ASA 5520 Reverse DNS lookup Issue

We are having Reverse DNS issues.

10.10.0.10 = Exchange Server

Windows 2003 = DNS server internal.

Setup: 1 to 1 NAT

10.10.0.10 smtp --> 70.89.133.218 smtp

Int gi0/2 = 70.89.133.217

Incoming Access Rule:

any --> 70.89.133.218 smtp permit

When we do a WhatismyIp on exchange server it says the IP is 70.89.133.217

It should be 70.89.133.217.

This is causing our email to be rejected from external sites due to reverse dns not returning 218. External people say are email is coming from 217. Comcast says the reverse pointer is setup correctly.

What are we doing wrong?

Thanks for any help you can offer.

3 REPLIES
Community Member

Re: ASA 5520 Reverse DNS lookup Issue

Correction:

When we do a WhatismyIp on exchange server it says the IP is 70.89.133.217

It should be 70.89.133.218

217 is the interface gi0/2 on the ASA.

Community Member

Re: ASA 5520 Reverse DNS lookup Issue

Can you show the specific "static" entry in your config for the NAT you're attempting?

Community Member

ASA 5520 Reverse DNS lookup Issue

did you ever figure out this thing with the reverse DNS showing PAT ip and not that of external MX record? What was the solution? Having same issue.

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