We've got two identical Dell PowerEdge 2950 rack-mounted servers, specified and purchased at the same time. One of the servers became obsolete (let's call it S2), so we're retasking it as an offline spare for the other server (S1), which is an SBS 2003 domain controller and Exchange server. We ran a successful full backup on S1, and did an Active Directory Restore Mode bare metal restore onto S2, using NTBackup in a dummy installation on S2. So far so good. S2 boots fine. I can log in using the existing Administrator credentials, and see file data, Exchange mailbox data, AD, etc. When I connect it to the network, I can ping other workstations on the LAN and get replies, ping Internet sites and get replies, as well as access Internet sites using a browser.
Here's my challenge. What I cannot do is communicate from anywhere else on the LAN to S2. So none of the workstations can ping S2. Although DHCP, DNS, and WINS are all running on S2, none of the workstations recognize the services because something is preventing incoming communication on S2 from devices on the LAN. Workstations don't recognize an existing domain controller for the same reason. Until I get this sorted, the offline backup is useless. The HALs should be identical on both computers. Any thoughts?