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Reverse DNS Lookups

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Reverse DNS Lookups - 6.Aug.2004 8:17:00 PM   
acira

 

Posts: 36
Joined: 14.May2003
From: Chicago
Status: offline
On occasion, I receive non-delivery reports saying that I don't have a DNS entry, delivery was refused.

The recipient email server is performing the dns reverse lookup. I know I need to verify that my ISP has a PTR for our domain. What else could cause the NDR? Also, is it okay to always leave the dns reverse lookup enabled?

Andrew
Post #: 1
RE: Reverse DNS Lookups - 8.Aug.2004 6:01:00 PM   
maprime12

 

Posts: 4
Joined: 8.Aug.2004
From: New York
Status: offline
Question,

Is your ISP also the owner of the IP address block that your domain sits on? If not, make sure that you get the owner of the address block to give authoratative permission for your isp to host your domain. You can pretty much find out what your domain setup is by performing an nslookup with the following syntax:

nslookup
set debug
Enter servername or IP address

If DNS is configured correctly, the mx record and corresponding A record will show up. Your ISP may need to configure classless reverse lookup. A good primer on this is available at Classless reverse lookup
Also, how many name servers are hosting your domain? It's always good practice to have at least two for failover. Hope that this helps.

Regards,

Marvin

(in reply to acira)
Post #: 2
RE: Reverse DNS Lookups - 9.Aug.2004 4:57:00 PM   
acira

 

Posts: 36
Joined: 14.May2003
From: Chicago
Status: offline
Our ISP hosts our domain.
I recognize two authoritative servers our ISP uses for our name servers.

I set up the MX record and corresponding A record which is the public address of my firewall. Also, I've seen pointer records at my ISP already setup. So, does this setup mean that my ISP is performing reverse lookups on email submitted to my domain?

Thx, AC

(in reply to acira)
Post #: 3
RE: Reverse DNS Lookups - 11.Aug.2004 9:09:00 AM   
Vitaly.K

 

Posts: 39
Joined: 30.Jul.2004
From: Kazakhstan, Almaty
Status: offline
quote:
Originally posted by acira:
Our ISP hosts our domain.
I recognize two authoritative servers our ISP uses for our name servers.

I set up the MX record and corresponding A record which is the public address of my firewall. Also, I've seen pointer records at my ISP already setup. So, does this setup mean that my ISP is performing reverse lookups on email submitted to my domain?

Thx, AC

hi acira!

you can try this address: http://www.dnsstuff.com/ and try different tools there to see whether your DNS is configured correctly.

have a nice day [Smile]

(in reply to acira)
Post #: 4

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