Connection dies frequently, is restored after dead peer detection

[Bernhard Schmidt]

Hi Matti,

> A couple of weeks back, my openconnect VPN connection started to freeze
> frequently. I'm not sure what changed at the time. The connection comes
> back after a while and I noticed from the logs that it is restored
> after a "DTLS Dead Peer Detection detected dead peer!" message. So I
> found the --force-dpd option and the situation is bearable, if I set
> the value to 2 or 3. What might be the problem? Is it a bug or a
> configuration issue? On client or server?

Your bugreport in Debian shows the cause

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=835587

I have just rebuilt GnuTLS with the necessary patches (unfortunately you
need four patches on top of GnuTLS 3.5.3 to apply cleanly) and will
submit the patch to the BTS asap.

Downgrading gnutls to
http://snapshot.debian.org/package/gnutls28/3.5.2-3/ should fix your
problem if that bug is correct.

Bernhard