Can Google ban IP Addresses?
 

I've read somewhere on a forum that Google will ban an IP address which hosts spammy web sites.

For example, let's say that there are 10 sites hosted on a shared IP server and one of the sites gets banned on Google as a spammy site thus banning all the sites in that IP address. Is this possible?

When I spoke with my hosting company they said that Google or other search engines cannot ban an IP address but they can ban a domain name. I agree with him about banning the domain name part but I'm not sure if it is realistic for G to ban an IP. I was trying to find the forum that I first read about this so I can forward it to my ISP, but I can't seem to find it. Any comments would be greatly appreciated.