Guests cannot read posts, can the search engines still index the site?

[TrudyD]

I've had some problems on my website with guests who have been reading all of the posts and then go elsewhere and causing problems for the site. Also I've had a run of registrations from those phony IP addresses, China, India, Japan, Russian, etc....

I've decided to make the posts viewable only to the registered members and only accepting registrations from people with valid IP addresses.

My question is....the search engines, being guests, are being blocked from the posts. Is there any way to fix this so the search engines can continue to index the site?