[Openvpn-users] Openvpn (v2.0.7) crashing my box

[David Rosenstrauch <darose@xxxxxxxxxx>]

Not sure what exactly is going on (and I unfortunately don't have much 
debugging info to supply) but openvpn is crashing - not just itself but 
my entire server!

Here's details as best I've got:

Config:
Linux Kernel 2.6.16.11
Arch Linux distro
openvpn 2.0.7
using tun (not tap) interface
using pre-shared static key


The problem first occurred last week.  I use the vpn to access IMAP on 
my home server from my work desktop using Mozilla Thunderbird, and 
generally everything works fine.  However last week, I came back from 
lunch to find that Thunderbird was reporting that it could no longer 
access the server.

I have ping/retry enabled in my config, and in normal use I'll see 
occasional messages that the connection timed out and is restarting, but 
these are pretty rare. (Maybe a handful throughout the course of a day.)

However, in this case when I checked my openvpn client logs, it was 
repeatedly timing out and trying to restart the connection.  I ctrl-c'd 
my openvpn client, then started it again.  I was able to make the 
connection again, but things were clearly screwed up.  The connection 
still kept dropping intermittently, and I was no longer able to ssh into 
the box over the vpn connection.  (Or via its external IP address on the 
Internet.)  And after a bunch more times trying to access the box via 
vpn and ssh, I finally lost all connectivity with the box altogether.

When I got home, I found that the box had completely crashed.  The 
screen displayed a stack dump of some sort, with the name openvpn 
displayed somewhere and thus appearing to be the cause.  (Sorry, but I 
don't have any of the stack trace details written down.)  I couldn't 
switch to a console (via Ctrl-F1, etc.) or ssh in to the box from 
another machine on my LAN - it was totally hosed.

I wound up having to power it off manually and rebooted, and after that 
everything seemed fine.  My logs (including openvpn.log, which I have 
set to level 3) showed no trace of any problem.


Since I had little info to go on, I gave up worrying about it.  But 
today I started to get the same problem happening again.  I didn't 
completely lose connectivity - but only because I called my wife and had 
her reboot the box before I did.  Same symptoms - connectivity errors in 
Thunderbird, no longer able to ssh into the box, my wife reported that 
her Windows box on our LAN (which uses the Linux server for DNS) lost 
internet connectivity (since it could no longer resolve any hostnames), 
etc.  Plus this time I tried pinging the server's vpn address (10.1.0.1) 
and found that many of the packets would not get through.

Again, what I was doing right before this happened involved Thunderbird. 
 I was that I was typing an email and hit File -> Save, which saves the 
current state of the email in my Drafts folder.  (I tend to do File -> 
Save frequently while composing messages; could this be somehow causing 
the problem?)  Beyond that, there was nothing unusual going on that I 
could see causing this problem.


Anyone have any idea what might be happening here and/or how to fix it? 
 (And, of course, if it would be helpful for me to post more config 
info first, please let me know.)  This is a really aggravating problem, 
and I'd really like to find a way to get it addressed.

TIA,

DR

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