I'm looking to potentially upgrade my Wordpress hosting to improve performance. I've read through How to find web hosting that meets my requirements?. However, before moving my site to a new provider, I'd like to "test" the hosts' performance prior to signing up.
I know that it's possible to lookup who hosts a particular domain, but are there any tricks to doing this in reverse? I.e., is it possible to look up what domains are using WordPress hosted by a particular hosting provider?
Alternatively, is there a way to see what IP address blocks a web host "owns"? If I knew the address blocks, I could look at what domains where hosted by IP address.