How To Implement TLS 1.3 for iRedmail Roundcube in Ubuntu

As many of you know, I use iRedmail for my personal email server and I run it on an Ubuntu 18.04 VM on Linode. No big deal right?

Well, periodically I like to check to make sure my SSL settings are using the most up to date security by running servers tests against SSL Labs. I decided I needed to implement TLS 1.3. It turns out, it's really easy if you are using Nginx like iRedmail uses!

For the iRedmail Nginx configuration, all you have to do is edit the /etc/nginx/templates/ssl.tmpl file and add TLSv1.3 after TLSv1.2 in the ssl_protocols section! Should look like this:

ssl_protocols TLSv1.2 TLSv1.3;

That's it! Do that, save the file and restart the Nginx daemon by running sudo service nginx restart!

Now I'm running TLS 1.3!