Please bear with me as I'm not a networking person by trade.

Our current configuration at work includes two Windows Servers serving as DHCP/Active Directory servers (if that makes sense) -- one replicating from the other. On both machines, the DNS resolution is set up as:

1. Main Windows Box (10...* address)
2. Public IP Address (for Verizon)
3. Public IP Address (secondary Verizon)
4. Secondary Windows Box (10...* address)

Assuming our domain is foo.com, we maintain the foo.com website on a hosted VPS with it's own IP address.

The problem is that even though bar.foo.com is an internal server and is defined in DNS on the Primary Windows machine, when I ping bar or even bar.foo.com it resolves to the hosted IP address instead of the 10.* address.

I tried taking both of the Public IP addresses out of the DHCP scope, and that seemed to work, but it completely slowed down access to any external sites, so that wasn't acceptable. I also tried adding the two Windows machine as the DNS servers on my desktop. That too worked, but I'd rather not have everything enter their DNS servers, as the above setup should theoretically be working.

Is there anything I could check to see why pinging bar.foo.com isn't resolving to the DNS entry on the Windows machines?

Here's a summary of the ping results, if they help:

Pinging from servers with static IP

bar.foo.com resolves with correct IP address

Pinging from linux machines not joined to the domain

bar.foo.com resolves with correct IP address

Pinging from user's desktop machines, joined to the domain, but dynamic IP

bar.foo.com resolves with incorrect IP address

This is driving me crazy!