What exactly is a C class IP? Your domain is associated with a certain IP address with a format like aaa.bbb.ccc.ddd . It is composed of 4 sets of number each from 0 to 255.

If your domain for example has an ip address of 192.168.0.1 it belongs to a C-class network of 192.168.0 and this C network has 255 ip-addresses which are from 192.168.0.0 up to 192.168.0.255.

Usually, your web hosting server has a lot of ip addresses which are on the same C-class.

There was a time when webmasters have a lot of websites and domain names and they normally host it in one web server. What they did to increase their search engine ranking is to interlink these websites to make it appear that each website is popular because of the many incoming links to it.

To prevent such webmasters from dominating the search engines with this technique, google gives more preference or importance if the links were from different C-class IP addresses. With such algorithm placed, webmasters who interlink their websites would be ranked lower if compared to sites where link come from different IP addresses (or different web servers).

Natural links come from multiple C-Class IP addresses and not from only one class C network. So make sure you know your IP address and get more links from other class C IP addresses.