The interlinking websites is generally discouraged because search engines such as Google penalize it quite badly. Search engines use the information of your IP address to find any interlinking within your websites. Websites that are all on the same shared server will have identical C Class IP addresses. This is why experienced webmasters advise against the interlinking of websites that share a server.
An IP address is made up of four groups of three numbers, e.g. abc.def.ghi.jkl. The third group of these numbers is referred to as the c block. Different web hosting companies will get different C class IPs from vendors. Thus, if you host your websites with different web hosting companies then the chances of your websites having the same C class IP address is very little. It is very important that your websites have different C class IP addresses.
For example, the following would be an example of identical C class IP addresses that belong to different webmasters:
The following would be an example of unique IP addresses:
It is also very important to note that C class IP addresses should not be all that webmasters may attention to ensure better rankings. Webmasters should practise other basic SEO methods as well. This will include uses systems that include keywords, key phrases, meta description tags, meta keyword tags, URLs and domain names. Also, webmasters should note that there are many websites that rank well with search engine even though they have the same C class IP addresses so they need not put too much time and effort into this aspect of SEO.