https://www.forum.directadmin.com/...
No it's not. Discourse is not fit for these kind of things and missing a lot of options.vBulletin is already a little obsolete.
@BBM, I believe my old post in reply #10 explains this: http://forum.directadmin.com/showthread.php?t=55692&p=285510#post285510
Redirect from www to non-www will not fix the certificate problem because the certificate warning will still appear. The TLS handshake is before the headers exchange.