I have a cisco router configured to handle multiple subnets (10.1.10.n, 10.2.10.n, etc), and an ubuntu system serving DHCP to the computers served by the router.

After a restart of the DHCP, the systems on the 10.1 subnet are fine, but neither the server or the computers configured on the other subnets can see the router at 10.2.10.1 (or 10.3.10.1, or 10.4.10.1). The router can see itself at 10.2.10.1, however.

The change that caused this was restarting the server, so I'm approaching it assuming the configuration error is on that end. Is that the likely issue or is there a different problem that would prevent the machines on the 10.2.10 subnet from resolving DHCP?