IP address is checked by using this tool. If shared hosting services are used by you then this tool will display the domains and links of other websites that share your IP address. If there is any problematic website then an icon will be displayed to identify the type of risk. 

Don't share your website's IP address on a website which contains malicious content as it will affect the Page Rank of your website. Also don't share your website's IP address on a website which contains spam as it will also affect the Page Rank of your website. Some webites are blocked by search engines and this will result in accidental blocking of those websites which share the same server or IP address. It is a best option to use dedicated web hosting. Use this tool for identifying those websites which share an IP address with your domaain. This tool also tells about the potential risks that can affect the page rank of a website.