Reverse DNS issues.

[Celinagroup]

We host our own DNS and the reverse lookup is not working, It seems to be configured correctly and I even put it on another box to test it. I'm trying to do an nslookup on say 12.1.129.5 and it doesn't work, but if I configure my system at home's DNS to 12.1.129.2 (Our external DNS server) then I can do an nslookup. The DNS sits behing a PIX 501, but I can't find any reason that would cause issues. All I know is tests show me it isn't working correctly and I am obviously missing something. Thanks.
12.1.129.5 would be mail.celinagroup.com BTW.

 

[ChrisAC]

There doesn't seem to be a PTR record ..

Query: 5.129.1.12.in-addr.arpa. Query type: PTR record
Recursive query: Yes Authoritative answer: No
Query time: 1212 ms. Server name: n/a

Answer:
5.129.1.12.in-addr.arpa. 83000 CNAME 5.0/25.129.1.12.in-addr.arpa.

Authority:
0/25.129.1.12.in-addr.arpa. 83000 NS ns.celinagroup.com.
0/25.129.1.12.in-addr.arpa. 83000 NS ns2.celinagroup.com.

You should have ..

5.129.1.12.in-addr.arpa. PTR mail.celinagroup.com

Chris.


**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[Celinagroup]

I agree it appears that I have no PTR which is my problem, because I have a Reverse DNS zone for 12.1.129.X and a reverse pointer was made automatically when i created the DNS record. I can go and look at it yet people outside can't see it. That seems to be my issue. Any thoughts as to why I have a pointer record yet my Name server says it can't find it. I only have one DNS server.

 

[GlenJohnson]

Need more info. Has this always been like this or did it just start?

Glen A. Johnson
Johnson Computer Consulting
MCP W2K
glen@johnsoncomputers.us


Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884
"Action is the proper fruit of knowledge."
Thomas Fuller (1610-1661); English scholar, preacher

 

[Celinagroup]

I am assuming it has been this way for a long period of time. I just recently took over the network and I found it wasn't working when dealing with some E-mail issues we were having. Thanks

 

[pgordemer]

Even if you host your OWN DNS to the outside world, typicall the REVERSE DNS is hosted by the ISP provider for the range of IP's you have.

You either need to have the ISP make the change in their reverse block, or deallocate the reverse IP lookup from their server and have it forwarded to your DNS server and you maintain it.

Talk to you ISP.

Phil Gordemer
Manager, Technical Support
CADD Value Corporation

 

[Celinagroup]

Which is where I looked at first. Our ISP however informed me that they have allocated it to me under the CNAME ns.celinagroup.com which is my DNS server. I'm out of ideas, but I figure I must be doing something wrong or else it would work. Any ideas are appreciated. Thank you

 

[GlenJohnson]

How long has the firewall been in place?

Glen A. Johnson
Johnson Computer Consulting
MCP W2K
glen@johnsoncomputers.us


Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884
"Action is the proper fruit of knowledge."
Thomas Fuller (1610-1661); English scholar, preacher

 

[Celinagroup]

It's been in place for atleast 2 years, the PIX allows reverse DNS on the same UTP port as Forward DNS. Our ISP tells me there is no other way to assign our reverse DNS other then a CNAME, does anyone know if it possible for a CNAME to cause issues with an NSlookup (Maybe because it doesn't know how to handle it)? I've used up all of my ideas so I'm curious because I can't do an nslookup from the internet, but if I statically assign our external DNS server as my DNS server I CAN do an NSLOOKUP.

 

[ChrisAC]

As I said, you need a PTR record. That is how reverse DNS works.

http://www.ntfaq.com/Articles/Index.cfm?ArticleID=13497

http://64.46.164.220/lycos/step/1,,9+50+26123+24913+1234,00.html

Chris.


**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[Celinagroup]

I agree I need a PTR record and it may be possible that I am misunderstanding you, but I have a reverse zone with associated pointer records that were made automatically. If I could paste a screen print in here I would, but maybe this will help. Do an NSLOOKUP on 12.1.129.5. It will not work, then go into your network setting and manually set your DNS server to 12.1.129.2 (Our external DNS) and then do the same NSlookup... It will now work which should mean the reverse lookup on the server is working. This is where I am at.
Thank you