Simple question about guest permissions
 

I'd like guests to be able to see the whole board* view threads etc BUT when they click on one they are taken to the log in screen. I don't want them to actually be able to read any posts/threads before logging in.

I currently have these settings for guests:

Can View Forum Yes
Can View Thread Content Yes
Can View Others' Threads Yes

Guests can see the board but instead of there being the last post visable* it says private and when clicked on it says 'there are no posts in this forum'. I don't want it to say this* I want it to prompt them to log in.

What have I not done?

Thanks.