Sudden VPN client issues with RX-AX82U

[zugu]

Hello everyone,

I am using an Asus RX-AX82U router to connect to a work VPN, as I am working from home. The default router firware does not allow a lot of OpenVPN configuration, so I installed the Merlin firmware some time ago and it has performed flawlessly until today.
This morning, without me performing any change and without the router auto-updating its firmware, I noticed it cannot connect to the VPN anymore. The log is attached.

The relevant line seems to be this one:

 OpenSSL: error:14094416:lib(20):func(148):reason(1046):SSL alert number 46

which seems to point to a certificate that is no longer accepted by OpenVPN. The strange thing is the OpenVPN GUI client I use on my desktop PC can still connect to this VPN without issue, using the same configuration/certificates. What could be causing this?

 

[bennor]

I am using an Asus RX-AX82U router to connect to a work VPN...

What firmware and firmware version are you running on the RT-AX82U? Gnuton? Or stock Asus?

Have you contacted the person in charge of the work VPN (assuming its not you) to see if they have changed anything on their end? Could be they may need to provide new setup instructions or cert file.

 

[zugu]

I contacted the IT department and they said this is what the OpenVPN server replies:

disconnected <TLS error: ssl: empty certificate chain received (6)

This happens even if the certificate, the CA and the keys are properly set on the router.

 

[eibgrad]

Merlin stores the certs, keys, etc., in the /jffs/openvpn directory. You could dump the relevant files and make sure they haven't been corrupted.

 

[zugu]

Checked the files in the specified location and they're OK.

 

[eibgrad]

Only thing I can suggest at this point is make a backup of the router config and JFFS, then reset to factory defaults, reconfigure the VPN, and see it now works. Worst case, you can always go back to where you are now.