OpenVPN 2.6 / OpenSSL 3 support

By 30th January 2023No Comments

Table of Contents

  1. Linux / Mac
  2. Windows

Please note that the stacks don't currently support OpenSSL 3, so you may encounter errors when trying to connect to your stack's VPN when using the OpenVPN 2.6 client.

Linux / Mac

You can convert the .p12 certificate file (from to a compatible format by running the following commands:

openssl pkcs12 -in stack1.c1.sonassihosting.com_sonassi.p12 -nodes -legacy -out temp.pem
openssl pkcs12 -in temp.pem -out stack1.c1.sonassihosting.com_sonassi.p12 -export

(Replace stack1.c1.sonassihosting.com_sonassi.p12 in both commands to match your .p12 file)


We'd recommend staying on the 2.5.8 OpenVPN client for the time being, which supports OpenSSL 1 instead.

If you need to use the 2.6 OpenVPN client, you can convert the generated .p12 file in a similar way as the above, but you'll need to specify the path to a required legacy.dll file too.

First, open a command prompt as the Administrator user, then specify the path to this legacy.dll file:

set OPENSSL_MODULES=C:\Program Files\OpenVPN\bin

(You can also download this file from if required)

Change directory to your OpenVPN installation:

C:\Windows\System32>cd C:\Program Files\OpenVPN\bin

C:\Program Files\OpenVPN\bin>

Then convert the .p12 file - press enter when prompted for an import password:

C:\Program Files\OpenVPN\bin>openssl pkcs12 -in "C:\Program Files\OpenVPN\config\stack1.c1.sonassihosting.com_sonassi.p12" -nodes -legacy -out temp.pem
Enter Import Password:

C:\Program Files\OpenVPN\bin>

and press enter again when prompted for an export password:

C:\Program Files\OpenVPN\bin>openssl pkcs12 -in temp.pem -out "C:\Program Files\OpenVPN\config\stack8.c545.sonassihosting.com_sonassi.p12" -export
Enter Export Password:
Verifying - Enter Export Password:

C:\Program Files\OpenVPN\bin>