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DNS Problems

By thenetworker ·
The problem that I am running into is that I have 2 domains, I am sure there are more that I do not know about, and both are resolving incorrectly, which of course makes them unreachable.
I am looking and looking, but am unable to find out where the DNS gets it's info from. When I do a query, where does my DNS server go to resolve the name? Kind of a basic question, but I am trying to find out why these are resolving incorrectly.
OS is Win NT 4.0.

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DNS Problems

by Astute In reply to DNS Problems

First check the whois database(I use http://www.allwhois.com to see which names servers actually resolve a domain) to make sure that your name server is listed there.

pls respond with that info.

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DNS Problems

by thenetworker In reply to DNS Problems

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by Stillatit In reply to DNS Problems

If you are talking about DNS domains, each domain as registered will have an authoritative server registered, and the whois <domainname> command will show you that. That address is where the DNS system will go for an "authoritave" answer. If that address is not your server (or a DNS server of your ISP, who is maintaining DNS information for you), you need to correct that before anything else.

It is possible (and often done) to have an official "Public" DNS server, but to have a separate DNS server inside your network which knows things that you do not want the world to know. In this case, the boxes on your LAN point to the private DNS server, which is set up to think it is the authoritative primary server. Anyone looking you up by coming down from the root servers will find answers from the "Public" DNS server.

A separate problem is whether or not each machine is looking at ANY server.

In NT, from a command window, type:
ipconfig /all
This will list the DNS servers which your machine is using (where they will go to look up names). Note that this may be different on each machine. (On windows 95/98, use winipcfg.)

If you are running DNS server on your NT, if your DNS server as reported by ipconfig is not your NT box address, you first need to change that (network properties).

Use nslookup to query the DNS. Start nslookup, and type help for a list of commands.

Good luck.

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by thenetworker In reply to DNS Problems

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by thenetworker In reply to DNS Problems

My DNS server is listed as the Name server for my domain. The 2 domains that I am having problems resolving are not my own.
Sorry, I think the way I stated the question was confusing. All the computers on my network can access any and all web pages without problem, except for 2 web pages. For these two sites, which are external to my network and out of my control, the DNS resolves the names to incorrect IP addresses, making them inaccesible.
I have secondary DNS services providedby my Internet Provider, and when using that DNS for name resolution, they are resolved correctly.

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DNS Problems

by cavedweller In reply to DNS Problems

It sounds like your internal DNS server is working for all your internal requests. Your clients should be (and apparently are) set up to query your DNS server. You DNS server should be set up to forward unknown requests to a 'parent' DNS server, usually this would be your ISP's.

The way your clients get DNS answers is to ask each of the listed servers, in order, until they are able to communicate with a DNS server. The first server contacted must be able to resolve the query. Clients DON'T go to the second server if the first one doesn't know! (only if the first one is unreachable). Your DNS server forwards unknown requests, waits for a response or timeout, then passes the response along to the requester.

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DNS Problems

by thenetworker In reply to DNS Problems

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by pdieten In reply to DNS Problems

One more thing you may have to check--you may have an error in the cache on your DNS server. NT DNS servers cache entries so they don't have to forward every request to the root servers. Use DNS Administrator to look in the cache for each of your DNS servers, find the domains you are having problems with, and erase the cache entries for those domains. Then try to access the sites again. With any luck the DNS server will request the correct IP addresses from the root servers and the pages will be found properly.

Good luck----

Cheers,
Paul

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by thenetworker In reply to DNS Problems

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by thenetworker In reply to DNS Problems

Well, I do beleive it was an issue with the cache, although I will not find out for sure unless it happens again. I rebooted the machine this morning, and all was well.
I awarded the tech points to the 2 answers I received that were on the correct track. Thanks for the help all.

- Mike Scott

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