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Question about setting up rDNS

dustinwk
dustinwk asked
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Last Modified: 2012-05-05
I have my MX record pointing to mail.mydomain.com
Then I have my A record for mail.mydomain.com pointing to xxx.xxx.xxx.46

xxx.xxx.xxx.46 is one of several ip addresses I have in a block
My primary address is xxx.xxx.xxx.17 so when I am on the internet that is the IP that people see from me. I set up my mail server on the .46 address because I thought it would be good not to have it on the one everyone sees.

I am having some messeges returned because I have not setup rDNS I am going to do this but I have a question about it.

should I call my ISP (qwest) and tell them to create an rDNS record for the .46 which is my mail server or does it need to be the .17 which is my primary. I dont know if they check to see if it is comming from .46 or not if they do they may say "hey this is comming from .17 and the rdns says it should be .46" does that make any sense?

I guess what I am asking is do I need to chainge my A record that my MX record points to so that it goes to my main ip so that I am sending and recieving over the same IP? Or do I just need to make an rdns record so that my main (.17) ip resolves to mydomain.com

Thanks
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Commented:
You need to setup a router that will use the xxx.xxx.xxx.46 address as it's WAN Interface IP Address and connect the router's LAN side to a second NIC in the server.

-saige-
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Top Expert 2007

Commented:
For mail service, the ip of the mx record (in your case pointing to A record) should have PTR record. So you need PTR record for .46 and for outgoing .17 also you need PTR record.
Make sure your mail server is sending from the .46 address. (maybe visit www.ipchicken.com from it). The PTR record for the .46 should be a specific hostname (say mail.mydomain.com) and mail.mydomain.com should point to .46. That should solve your rDNS problems.

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