Using Netcat (nc) to query OpenVPN management interface

luckman212

Based on this old thread I am trying to create a simple shell script to query the status of a particular openvpn tunnel using netcat so I can attempt to auto-restart it if it goes down.

I tried the following variations of the commands

printf "state 1\r\nexit\r\n" | nc -U /var/etc/openvpn/client1.sock

printf "state 1\nexit\n" | nc -U /var/etc/openvpn/client1.sock

echo -e 'state 1\nexit\n' | nc -U /var/etc/openvpn/client1.sock

each of those output

>INFO:OpenVPN Management Interface Version 1 -- type 'help' for more info

and then immediately exit without printing the "state" portion

printf "state 1\r\n" | nc -U /var/etc/openvpn/client1.sock

successfully outputs the VPN status but then "hangs" in nc, I have to CTRL+C to get out (even typing 'quit' does not exit)

I am on 2.3.2_p1. Has anyone got any idea how to successfully query this status via script? I looked at the PHP code in the OpenVPN widget and it is using a similar socket interface.

luckman212

Well, nobody answered but I figured out a workaround. Not sure if this is correct or safe but FWIW adding the '-w 1' option causes the nc to time out after 1s which effectively "solves" this problem:

printf "state 1\r\nstatus 2\r\n" | nc -w 1 -U /var/etc/openvpn/client1.sock

danmanners

@luckman212, unbelievably late to the party here but thank you, this is exactly what I was looking for! Much appreciated for you putting your solution!

adopilot

@luckman212 apologies for bumping post after 4 years,
But Can you please show your ssh command for restarting open-vpn client on pfsense.

heper

is there a reason not to just get it from the developers shell ?

adopilot

@heper I did not get you?

We are using ssh as some kind of pfsense api, and reading openvpn status through ssh is made by app We also want to send ssh command to restart vpn.

heper

https://forum.netgate.com/topic/131539/how-to-restart-openvpn-in-a-script?_=1605713288301

heper

status can be acquired by changing 'restart' to 'status'

[root@pfsense.lan]/root: pfSsh.php playback svc status openvpn client 1