How to link a tunX interface to a specific OpenVPN instance?

Question

I known that I can give a specific name to the TUN interface using --dev option, but I didn't and I have now on a router machine something like a hundred client configs. with less clients I was able to dig the log to search for the name of the interface and link it to a named config file, but now there is too much activity.

I have played for a while with lsof and udevadm but I'm still not able to link a specific tunX interface with an OpenVPN instance.

I would like to know which OpenVPN instance/config-name/process is linked to a specific TUN, like tun4 for example, is there a solution for that?

Be it for openvpn or a VM, it's the same: How to find the connection between tap interface and its file descriptor?. You can link it to the correct running process among candidates (openvpn processes) and hopefully to its config file — A.B, Aug 15 '18 at 15:44

score 1 · Accepted Answer · edited Aug 17 '18 at 02:14

1

So I came with a solution inspired by A.B comment.

$ ps ax | \
  awk '/[o]penvpn/{print $7" "$1;system("grep iff /proc/"$1"/fdinfo/*")}'`

which give me both running config and it's linked TUN interface.

edited Aug 17 '18 at 02:14

slm

369,824

answered Aug 16 '18 at 05:48

dominix

610

How to link a tunX interface to a specific OpenVPN instance?

1 Answers1