But the OpenVPN connection auto-restarted very often:
IDC private network--OpenVPN server(126.96.36.199)--OpenVPN client(188.8.131.52)--Office private network
The connection speed never exceeded 5 Mbps (our office's bandwidth is 100 Mbps).
Tue Nov 6 10:47:49 2012 Preserving previous TUN/TAP instance: tun1
Tue Nov 6 10:47:49 2012 Initialization Sequence Completed
Tue Nov 6 10:50:27 2012 [server] Inactivity timeout (--ping-restart), restarting
Tue Nov 6 10:50:27 2012 TCP/UDP: Closing socket
Tue Nov 6 10:50:27 2012 SIGUSR1[soft,ping-restart] received, process restarting
Tue Nov 6 10:50:27 2012 Restart pause, 2 second(s)
The connection always stalled during the first MB of a file transfer.
I googled for a long time, tried every possible fix of this problem: changed MTU size, upgraded OpenVPN software, modified the configuration of the core switch. No use at all. I doubted that it is the internet connection of our office that causes the problem.