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I setup new network,

1> DC & DNS

2> Gateway

XXX Other app servers

I don't get anything when try nslookup, It comes back with unknown.

All server can access internet and dns entry is pointing to server <1> so dns on server <1> works fine, i guess.

What could it be?

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what are trying to resolve using nslookup? Are you pointing nslookup to right DNS server for name resolution? something like nslookup - <DNS.Server.IP> –  KAPes Aug 17 '09 at 18:13
    
I think nslookup finds default dns server, i am just using nslookup –  mamu Aug 17 '09 at 18:43
    
-1 for posting vague summaries instead of actual and litteral results –  bortzmeyer Oct 6 '09 at 8:00

3 Answers 3

Based on the sparse info in your post I'm guessing that when you type nslookup from a command prompt it is saying something like this:

"*** Can't find server name for address w.x.y.z: Non-existent domain". Or "Default Server Unknown".

What this means is that you don't have a reverse lookup zone. A reverse lookup zone is not required and will not affect the normal operation of the DNS server or clients. If you want to get rid of the message, set up a reverse lookup zone for your subnet.

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When you go to a command prompt and type "nslookup" the response will be something like this:

Default Server: dnsserver.domain.TLD
Address: [DNSServerIPAddress]

>

If the DNS server that you expect is not shown in the "Default Server:" then that PC's DNS settings are suspect. It could be that the DHCP options aren't set correctly or if you use static IP information on that PC, those aren't entered correctly. Otherwise, there is a basic TCP/IP connectivity problem...

Question 1: Can you ping the DNS server?

The DNS server itself will be set to point to itself for DNS and the DNS service will by default look to root hints for resolution. You may want set up forwarders as Cédric Boivin has suggested. However, I'd suggest OpenDNS for speed, security and reliability reasons. Check out this tutorial to set up forwarders.

Question 2: Does nslookup behave this way on all computers in the domain?

Question 3: Does nslookup behave this way on the DNS server itself?

At the end of the day, I'd suggest using Network Monitor on the affected PCs and using a capture filter for DNS traffic to see what is and is not being transmitted and what, if any, error codes are being returned.

Question 4: Are you sure that the hardware firewall doesn't have a rule that manipulates DNS traffic at all? It could be set to block DNS traffic under certain circumstances.

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Whoes the DHCP server ?

When you make a ipconfig /all on other server DNS and Gateway are good on it ?

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there is no dhcp setup right now, i manually setup gateway, ip and dns. All are good as setup as per nic status –  mamu Aug 17 '09 at 18:42
    
Did your internal DNS server foward to another DNS server unknow DNS request ? –  Cédric Boivin Aug 17 '09 at 20:24
    
No I didn't change/setup anything for forward DNS, does it need to be setup? or would it send to gateway if can't resolve it and gateway would pass it to it's dns from external world? –  mamu Aug 18 '09 at 13:54
    
DNS forwarding has to be configured in the DNS server, it is NOT automatic. If you don't need internal DNS, I would simply point to the external DNS servers provided by your ISP. If you do need internal DNS, then configure that to resolve unknown hosts through the DNS servers provided by the ISP. –  wolfgangsz Aug 21 '09 at 14:14

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