When a windows client is connected to a server, disconnects are experienced.

This is because the client does not communicate (default 2 hours) whith the server and then other devices (like a firewall with a 1 hour inactive disconnect setting) disconnects the session.

You can change the keep alive settings as follows:

1. Open the register
2. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
3. Add/Change the Keepalive time

   KeepAliveTime

   Value Type: REG_DWORD – Time in milliseconds
   Valid Range: 1 – 0xFFFFFFFF
   Default: 7,200,000 (two hours)
   Description: The parameter controls how frequently TCP tries to verify that an idle connection is still intact by sending a keepalive packet. If the remote computer is still reachable and functioning, the remote computer acknowledges the keepalive transmission. By default, keepalive packets are not sent. A program can turn on this feature on a connection.

Microsoft knowledgebase 314053