Question : DNS resolution issue

I cannot connect to or ping some internet sites from my office network that I can ping/connect to from home. This problem only developed recently (or was noticed recently).

The network at the office (which a former admin did the set up for) is configured like this:

DSL internet connection (PPPoE) with a dynamically assigned IP address.

The router (basic Linksys BEFSR41) status shows the IP address and then has:

Static DNS 1: 67.69.236.1
Static DNS 1: 207.164.234.129
Static DNS 1: 0.0.0.0
MTU: 1492

The router is connected to a WIndows 2003 Sever, that is acting as a DC, and providing DHCP and DNS to the client PCs on site.

The network card of the Server has DNS Servers configured like this:
Primary DNS Server: 192.168.0.10 (the internal static IP of the server itself)
Secondary DSN Server: 209.226.175.224
Then under Advanced... it has a 3rd DNS server listed as: 198.235.216.110

I cannot ping those two public addresses from inside or outside the office.

The DHCP scope is configured to only hand out the local 192.168.0.10 address for DNS.

If I type: nslookup at the command prompt on the server, it returns:

"*** Can't find server name for address 192.168.0.10: Non-existent domain
Default Server: Unknown
Address: 192.168.0.10"

How can I troubleshoot and resolve the issue of not being able to connect to or even ping certain sites on the Internet?

Thanks,
IT_Service

Answer : DNS resolution issue

You need to check the configuration of the DNS services.

Under DNS, right click and choose properties for the server.  You need to look at the forwarders tab which you will need to populate.  A common choice is opendns.org whose IP addresses are 208.67.222.222 and 208.67.220.220.  This will ensure that your main server is able to resolve IP addresses correctly.

On the server itself, change the DNS settings under TCP/IP and make it 127.0.0.1 only.