On a Windows2003 server, should the DNS of the loopback network be the same as that of the other "Local Area Connection", or can they be different?

This is because I was able to ping the IPs in my loopback until somebody who tried to help me with something else changed a setting for the loopback, which prevented me from doing so now. Besides DNS for Loopback's NIC, can there be other possibilities which prevents me from pinging the IPs?

Thanks.

If the server is a DNS server, then using 127.0.0.1 as DNS is fine. However I wouldn't reccomend it as it is a potential security risk, it's better to do lookups on remote servers.

The loopback connection should not have any DNS configured, as any traffic going through this interface just goes back to the same machine again.

DNS is not related to pinging IP's, if you can't ping an IP you have a routing/networking problem, nothing to to with DNS at all.

Dan