Trouble with openvpn and /dev/tun

[Dirk Liebke]

Hi all,

after upgrading from dfly 1.1 to HEAD as of 2005/07/0 i am having some
problems with openvpn. Openvpn (1.5) is configured to run udp and uses
/dev/tun to connect my dfly-box to FreeBSD-4.11. Both ends of the link
connect properly and the tunnel is established.

Now to the problem:
If i try to open a telnet/ssh session over my secure link it takes
a few minutes to establish and is practically unusable because of high
latency. Next i tried to ping the freebsd-box from my dfly-box. The ping
stalls for about 30s and then receivs a storm of replys with decreasing
round trip times from around 30000ms to 120ms. Packet loss is about 10%.

If i do the reverse thing and ping from freebsd i get round trips from
about 120ms and no packet loss. A fresh port of openvpn-2 shows the same
asymmetrical behaviour.


- Dirk