Closing serendipity down

[Martin Marcher]

Hello,

I just recreated our company internal blog. Before that (and before  
going down) it was reachable only by a private IP, now I'd like to  
have it public - well in a way.

I'd like it to have only a login mask and none of the posts should be  
publicly available, that is until you have an account where you  
should be able to reach everyting.

Anybody knows how to do that or knows a plugin that can do that?

thanks
martin