Is there something I can add in the htaccess to allow search engines to index a section of the forum that I ccurrently have set as

$warningForums=array(1,2); in the bb_plugins.php file?

I would like it where they will still crawl, and when the search engines index the page, and then users click on it, they have to login.

I have a list of some search engine ips.

Thanks!

It's impossible.

Search engine is like a "guest" on your board. So if you disallow guests, you disallow search engine as well.

I think it would be possible to handle search crawlers' IP addresses some way, but I doubt it is worth to implement... First of all you need to have a list of ALL IPs which is near to impossible, since search engine companies are constantly upgrading their servers and changing locations probably. Thus that way you can't know about "new" IP-address of the unknown search engines.

I agree with Paul - whatever your "guest" visitor can access is what search engine crawler accesses too (so it won't index pages available only after you log in, but anything else is indexeable).