We use Gmail for our company email. I would like to limit sign-ins and account creations to only emails using our domain.
I also would like to make the whole forum secure by moving auth before accessing rather than when posting.
First of all, if you would like to limit access to your forum you should make it private. For example, go to your Project settings -> Community forums (Knowledge bases, etc) -> Privacy. Then mark it as a private. Then you can add your domain into access list like @yourdomain.com. Then only users with email in your domain will be able to access your forum.
Also, if you would like to see your forum on your domain (sub-domain) just set it up in the Project settings -> Project -> Domain aliasing.
Thank you for the request.