I have been working on this for the last couple of hours now with no luck. I have an SBS 03 Prem R2 box and as of this afternoon network connectivity has been down. The client computers cannot connect to the server at all. I can ping the clients from the server but the clients cannot ping the server. The clients can ping each other and the router though. I have checked all of the usual suspects. First checked the cable from the server to the switch, its good. Tried a different port and it didn't change anything. DHCP is running, DNS is running, IPSEC is running. There have been no major changes done in the last 24 hrs. I went as far as going out and buying a new NIC and I'm still having the same problem. I also bypassed my switches and connected the server to a different switch and connected my laptop to the same switch and tried to ping it with no luck. I am at a complete loss here and I don't know what I am overlooking. Any suggestions??