Question : Itermittently losing connection to the SBS 2003 local IP Address

I have a SBS 2003 implementation that has two NIC installed.  The first provides acces to the LAN and the second is connected to the public internet.

Everything appears to work fine; however, clients who are connected to the server keep losing the ability to connect to the server using it's local static IP address.

When they initially login to the domain they are able to PING the server directly; however, after a period of minutes or hours they become unable to PING the server.  Then, for no apparent reason it becomes available again.

This behavious also happens when I connect remotely using the VPN; however, I notice that if I disconnect and then reconnect it always establishes the connection and I am able to PING the server again.

Answer : Itermittently losing connection to the SBS 2003 local IP Address

if they can't ping, you also might have a look at 3rd party firewall/AV software running on the server/clients.
Also, update your NIC drivers, that also solves alot of issues.