OpenVPN Server Certificate No Longer Fits

[SevenFactors]

A couple of months back I successfully setup an OpenVPN server: RT-N66U running ASUSWRT-Merlin

Then a month or two later I ran into some issues upgrading from 3.0.0.4.354.30 to 3.0.0.4.372.30. To solve the issue I had to reset the router.

I once again am in need or having a working OpenVPN server. Of course, I'm going to reuse my previous OpenVPN generated keys, certificates, etc. Well, to my inconvenience, the certificate doesn't fit in the box.

Under ASUSWRT-Merlin v3.0.0.4.374.33_0 192.168.1.1/Advanced_OpenVPN_Keys.asp it says:

Only paste the content of the ----- BEGIN xxx ----- / ----- END xxx ----- block (including those two lines).

Limit: 3499 characters per field


My server certificate from: Certificate to -----END CERTIFICATE----- the character count = 4042

As you all know, there is more to the server certificate than just -----BEGIN CERTIFICATE----- ~ -----END CERTIFICATE-----

Please help/advice.

Thanks

 

[RMerlin]

Just to repeat the explanation on Twitter and elaborate on it (Twitter is useless for any tech support with its 140 chars blurbs, and I ain't doing my Captain Kirk impression with "Sentences. Short ones. Must save. Config! ...Reboot!").

OpenSSL generated certificate are outputed both in X.509 and Base64-encoded DER format. The content between BEGIN/END is the Base64-encoded version of the DER binary file. This is what you are using with OpenVPN.

If you use a base64 decoder to decode that block and save the result to a file with the ".der" extension, you can double-click on it in Windows to display it. If you look on the Details tab, you will see the same kind of info you were seeing in the X.509 section of the cert.

 

[SevenFactors]

Thanks for your time and clarification.

The OpenVPN server is up and running nice and smooth.