Have you verified it's not a DNS issue? something like ping 8.8.8.8
Also I have seen times when reconfiguring the routing gets hosed. From what I gather, this was once in server-gateway mode then change to server only. If so does it have 2 nics? It's possible a reconfig from the console could set things back to working.
In some older systems I ran into several upgrades where if the internet nic was live, the routing was f'ed.