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Windows 2008 DNS server forwarding issue ???

Hi Experts,

I'm running SBS 2008 domain and I use SBS inbuilt DNS server to forward my external requests. I have added my ISP's DNS server in to the "Forward" list. Both DNS server are identifying and this was working fine from past couple of months. But from yesterday users are getting time outs (DNS issues) when they are browsing.

I have added ISP DNS to client's machine then and then situation will be ok.

how do I troubleshoot this ??? Please advices ??

Thanks a lot !

halejr1

First what are the DNS settings on your interface of the server?

I would check using NSLOOKUP and pointing directly to the servers provided by your ISP. Also make sure that port 53 is open for DNS traffic. It sounds like your ISP may be having the issues, and you could allow forward lookup to standard recommended dns hosts if you set your servers DNS server to itself.

It doesn't sound like a browser issue if you are having the same problem via multiple browsers. Just do some basic IP troubleshooting, i.e. ping , tracert, etc. etc.

Good luck
Let me know what you find.

Shakthi777

ASKER

The timeouts still happening with the ISP DNS server in the client machines. But it's resolved temporarily (for about 15 minutes) when I do ipconfig /renew

Please advise !!!!

Shakthi777

ASKER

ok thanks halejr1: I'll try with your command line tools and post you result ! BTW the SBS server is running on VMware ESXi

:::Server Interface:::
 
Ethernet adapter Local Area Connection:
 
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Intel(R) PRO/1000 MT Network Connection
   Physical Address. . . . . . . . . : 00-0C-29-BB-58-97
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::4c51:b8fd:e0ea:c2d5%10(Preferred)
   Link-local IPv6 Address . . . . . : fe80::d550:5f5a:24f6:cae9%10(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.1.1(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 192.168.1.254
   DNS Servers . . . . . . . . . . . : fe80::d550:5f5a:24f6:cae9%10
                                       192.168.1.1
   NetBIOS over Tcpip. . . . . . . . : Enabled

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halejr1

ipconfig /renew -- on local system? shouldn't matter, if you've got a lease and the parameters don't change, renew won't do anything for you on a client machine.

your IP address, Default Gateway and Subnet mask probably don't change

Also, do an IPconfig / all from you local "problem" PC's. If you have static DNS entries, this too could be a problem.

Shakthi777

ASKER

ipconfig /renew -- on local system?
YES
shouldn't matter, if you've got a lease and the parameters don't change, renew won't do anything for you on a client machine.
BUT IT'S STARTING BROWSING !

Also, do an IPconfig / all from you local "problem" PC's. If you have static DNS entries, this too could be a problem.
I DID, ALL ARE CORRECT !

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suppsaws

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halejr1

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Dave Stringfellow

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Shakthi777

ASKER

ok Dave I have did exactly what you have explained. But when I'm unchecked IPv6 my out look clients are not connected to the SBS server, then i have enabled it again and not it's connecting. and so far I didn't get DNS issues.

And what about the root hints ?? Do I need to "Copy from the server" ???

Shakthi777

ASKER

Dave; it's happened again, below is the nslookup details; actually my DNS server IP is not 192.168.1.1 !!!!

I think some serious thing is going on, something is changing my client's DNS entry, and the thing is it will again get back to normal when I do ipconfig /renew

Please advise !!!!

C:\Users\hsn>nslookup
DNS request timed out.
    timeout was 2 seconds.
Default Server:  UnKnown
Address:  192.168.1.1
 
> www.google.com
Server:  UnKnown
Address:  192.168.1.1
 
DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
*** Request to UnKnown timed-out
>

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Dave Stringfellow

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suppsaws

I also didn't see an ipconfg /all of the server + one client, and also not how the clients were joined to the domain?

Shakthi777

ASKER

Thanks for all you valuable comments and I have learned a lot ! I have found one of my network users running test DHCP server.

Again thanks for your great support !

halejr1

Shakti --

what version of antivirus are you running on your server? Just a thought with a similar problem that I had in a previous life.

Need that IPCONFIG /ALL from the server and one or more of your clients.

Thanks.