Ask Ubuntu is a question and answer site for Ubuntu users and developers. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

On my OpenVPN server, I'm getting messages from OpenVPN like:

 ovpn-server[2455]: host/ IP packet with unknown IP version=15 seen

I have three OpenVPN clients and each of them give this error every minute.

A quick Google search makes it sound like this issue happens when one side is not using compression. But, in my setup, both the clients and the server have compression on.

Some of the clients are 12.04 and some are 12.10. The server is running 12.10, but all of the clients give the error.

Any thoughts on this?

share|improve this question

I just had this same thing and found that my client configuration was set to: dev tap

While my server configuration was set to dev tun

They were trying to operate in two different modes and getting confused. Might you want to check this between your two configuration files?

I set both of them to what I really had wanted to do which was: dev tun and the logs stopped getting filled up with those errors.

share|improve this answer
Both the client and server configs have "dev tun" set. – tubaguy50035 Jan 4 '13 at 15:22
I had the linux server set to tun and the windows client set to tap. Thanks a lot for the advice. – Gonzalo May 18 '13 at 0:42
This can also happen if you have LZO compression enabled on the client side but not on the server. – Léo Lam Aug 19 '15 at 15:09

I had exactly the same issue on a Linode machine - perhaps it is related. There's an investigation and fix by Dan McGee here:

echo 'lo' > /sys/module/aoe/parameters/aoe_iflist
share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.