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I think you have full NAT configured (or one-to-one NAT).<br />
<br />
So, simply ask your ISP to add a reverse DNS record on your @IP 1xx.2xx.1x1.xxx. Your ISP can add reverse DNS on all @IP that he deliver to you.
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I think you have full NAT configured (or one-to-one NAT).

So, simply ask your ISP to add a reverse DNS record on your @IP 1xx.2xx.1x1.xxx. Your ISP can add reverse DNS on all @IP that he deliver to you.

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ARIN provides utilities for this.<br />
<br />
Everything you should need for this can be found <a href="https://www.arin.net/resources/request/reversedns.html" rel="ugc">here</a>.
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ARIN provides utilities for this.

Everything you should need for this can be found here [https://www.arin.net/resources/request/reversedns.html].

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Please close this question.
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What didn't work exactly?<br />
<br />
Have you delegated NS authority for your IP blocks to a nameserver you can add a PTR record to?
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What didn't work exactly?

Have you delegated NS authority for your IP blocks to a nameserver you can add a PTR record to?

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Hi, is this still an issue?
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I have two PTR records already setup with my ISPs for rDNS. I also have two IP blocks from ARin.net. My email is coming/going &nbsp;on this IP 1xx.2xx.1x1.xxx from Arin. This IP is nat'd back to the spam filtering appliance which in turns forwards it to the exchange server.<br />
<br />
Example: When i email someone that checks for rDNS the IP they see is 1xx.2xx.1x1.xxx (Not the ISP IP address). how do i assign a hostname to this IP?
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I have two PTR records already setup with my ISPs for rDNS. I also have two IP blocks from ARin.net. My email is coming/going  on this IP 1xx.2xx.1x1.xxx from Arin. This IP is nat'd back to the spam filtering appliance which in turns forwards it to the exchange server.

Example: When i email someone that checks for rDNS the IP they see is 1xx.2xx.1x1.xxx (Not the ISP IP address). how do i assign a hostname to this IP?

Reverse DNS with IP range from Arin

Exchange is the server side of a collaborative application product that is part of the Microsoft Server infrastructure. Exchange's major features include email, calendaring, contacts and tasks, support for mobile and web-based access to information, and support for data storage.