[@robin-w Moderator 8 years, 3 months ago]

I would like to create a forum that is free for all to view but can only be contributed to by registered user of the website. So creating new topics and replying/commenting in the tread is only available to those who are registered. However anyone can read the thread and hopefully its contents will be searchable by google

This is the default.

If you set then forum to public, but ensure that anonymous posting is off

dashboard>settings>forums>anonymous posting

Then all can see, but only registered users can post

bbpress just uses wordpress login, so any wordpress login will work, so logging onto the website also gives access to the forums