shorten up the time connections "wait" before Windows really, really closes them. To do this, add the following HEX/DWORD entry to the local registry of your client system. By default, the implicit value is "120", which means a time out of 2 minutes. You can pick a value of TcpTimedWaitDelay down to "1", but a higher value is recommended.
HKEY_LM\System\CurrentControlSet\Services\Tcpip\Parameters\TcpTimedWaitDelay = 30 (decimal)