SBS 2003 server, all workstations XP pro sp3, 24 port 10/100 unmanaged switch, linksys router, Charter cable. RRAS is enabled, windows firewall is off. DNS and DHCP enabled on the server. Everything was working normally yesterday. Today workstations can't access server. Server can ping router and public DNS server. IE also works from server. Can ping some workstations but not all. All workstations also have internet access and pings between workstations work. Workstations can't ping server. I have replaced the switch this morning didn't help. Also checked properties of server NIC seems normal. Have tried changing ports in switch. Any ideas??