banning question
 

I've had some recent users register from an ip address that resolves as localhost. They all start with 113.168. or 123.27.
I've checked for users and only spammers on my forum are using that ip. Can I safely ban 113.168. and 123.27. ? I'm just concerned because they resolve to localhost and I don't know if that would effect my server assuming its the localhost. thanks