openvpn.md

OpenVPN common errors

Inconsistence warnings

You might see some warnings for Private Internet Access and others, similar to:

openvpn: Sat Feb 22 15:55:02 2020 WARNING: 'link-mtu' is used inconsistently, local='link-mtu 1569', remote='link-mtu 1542'
openvpn: Sat Feb 22 15:55:02 2020 WARNING: 'cipher' is used inconsistently, local='cipher AES-256-CBC', remote='cipher BF-CBC'
openvpn: Sat Feb 22 15:55:02 2020 WARNING: 'auth' is used inconsistently, local='auth SHA256', remote='auth SHA1'
openvpn: Sat Feb 22 15:55:02 2020 WARNING: 'keysize' is used inconsistently, local='keysize 256', remote='keysize 128'
openvpn: Sat Feb 22 15:55:02 2020 WARNING: 'comp-lzo' is present in remote config but missing in local config, remote='comp-lzo'

It is mainly because the option disable-occ was removed for transparency with you.

Private Internet Access explains here why the warnings show up.

Interrupted system call

It may happen, quite rarely though, that Openvpn is killed in a loop by the host system.

Even if it runs in a container, because it shares the tunnel device with the host, the host can make it fail.

If you get regularly in your logs

openvpn: Sun May 10 19:23:37 2020 Initialization Sequence Completed
openvpn: Sun May 10 19:23:45 2020 event_wait : Interrupted system call (code=4)
openvpn: Sun May 10 19:23:45 2020 ERROR: Linux route delete command failed: external program exited with error status: 2
openvpn: signal: killed

It might be another app you have interfering with the /dev/net/tun device and thus killing openvpn.

For QNAP users, it may be the QCenter. More information on this issue and many thanks for @AlexAlbright for finding the root cause through trial and error 🎈