Hi, i recently have problem with my server. Before it was ok but when i tested it today it gives me the following error. [code]Fri May 04 01:17:55 2012 us=453000 WARNING: Bad encapsulated packet length from peer (15464), which must be > 0 and

Hi, I am also facing same problem @ https://forums.openvpn.net/topic14131.html [code]sun Oct 20 09:57:17 2013 195.135.82.59:4040 WARNING: Bad encapsulated packet length from peer (4930), which must be > 0 and

Bad encapsulated packet length from peer

ricohard

Hi, i recently have problem with my server. Before it was ok but when i tested it today it gives me the following error.

Fri May 04 01:17:55 2012 us=453000 WARNING: Bad encapsulated packet length from peer (15464), which must be > 0 and <= 1544 -- please ensure that --tun-mtu or --link-mtu is equal on both peers -- this condition could also indicate a possible active attack on the TCP link -- [Attemping restart...]
Fri May 04 01:17:55 2012 us=468000 Connection reset, restarting [0]

I use TCP port 80.
I search the net for possible solution but didn't find the right answer. But i run allong one thread saying that is was just a problem with the DNS entry and i also suspect that it is cause by wrong DNS entry since when i try to access my ip on a web browser it returns http 502 Bad Gateway error which it shoudn't since the port is used by openvpn and not by http. openvpn can't see these.

My problem is i don't know anything about the wrong DNS entry and how to fix these on centos. Can anyone help me what to do not only for me but also for future using facing the same problem?

janjust

did any of the client or server configs change? it is also very well possible that someone is sending non-VPN traffic to your server at TCP port 80 (it's the web server port), which could trigger such warnings.
Without config files and log files of a connecting client it is impossible to tell what is going on.

sofo

Hi,
I am also facing same problem @ https://forums.openvpn.net/topic14131.html

sun Oct 20 09:57:17 2013 195.135.82.59:4040 WARNING: Bad encapsulated packet length from peer (4930), which must be > 0 and <= 1350 -- please ensure that --tun-mtu or --link-mtu is equal on both peers -- this condition could also indicate a possible active attack on the TCP link -- [Attempting restart...]

From above log what I understand is It is just terminating a single client connection where the Big packet coming from .
and that must be a openvpn client only.

If any big packet comes from internet to TCP 80 openvpn will just drop it because openvpn server can check that packet is not a openvpn packet. I think somehow from client machine big packet than expected getting into TCP tunnel.

And it s mainly happening once clients initial sequence completed soon after that server printing that message and restarting connecting.

Thanks