Reverse IP domain check tool that takes the domain name or IP address of a web server and searches for other sites known to be hosted on that same web server. Knowing the other web sites hosted on a web server is important particularly for those on shared web hosting plans. You don’t want to be in the same server where there are hundreds of other sites, or questionable content there, or being used by website actively sending email (can be considered as spam). When you are in the same server as other website which is detected as spammer, you email too can be identified as spam, because you have the same IP.
Try http://www.myipneighbors.com/
