Network middleware filtering udp proto tunnels?

briencolwell

Hi all, I could use a second opinion on this situation and appreciate your feedback.

I've seen strange behavior in some tunnels in China and Southeast Asia. These tunnels are UDP, shared key, site-to-site to a major network hub, where only one side has a remote hose (the other side listens). The strangeness I see is that the tunnel stops routing occasionally. Both sides see the connection from the other side (with correct IPs, verified from the logs), but no other packets reach either side after the initial connect. It seems strange to me that the tunnel connects via UDP but does not route packets via UDP once connected, almost like the issue is with my openvpn config rather than the network. Again, this behavior happens infrequently. Also I've verified the drop does not correlate with an IP change on either side, even though both sides are set up to float.

I'm wondering has anyone experienced intermittent drops with UDP site-to-site tunnels? What have you looked out for?

My client and server args are below.
# CLIENT
--comp-lzo
--float
--ping 10
--ping-restart 60
--persist-tun
--persist-key
--persist-remote-ip
--user nobody
--group nogroup
--mtu-test # SERVER
--comp-lzo
--float
--ping 10
--ping-restart 120
--ping-timer-rem
--persist-tun
--persist-key
--user nobody
--group nogroup

TinCanTech

briencolwell wroteIt seems strange to me that the tunnel connects via UDP but does not route packets via UDP once connected, almost like the issue is with my openvpn config rather than the network

As you have no routing in the configs you have posted it sounds like the absolute opposite to me.
ie. The issue is with your network.