We recently added a third server to our network. Originally, we had 2 Windows 2003 servers; both domain controllers, both running DNS. We never had any problems, the servers we always available to browse to or to ping by name or IP. After adding a new Windows 2008R2 server (which is also a Domain Controller and DNS server), we are having trouble seeing both of the old servers on the network at the same time. You can always ping them both, and if you search for \\servername, it opens right up, but only one will show up in the Network Places at a time. And, the one that doesn't show up cannot browse the network.
Can anyone give me some ideas why all three can't exist together?