Class C IP’s and SEO – an Introduction

One factor in SEO which many people are unaware of is the effect of Class C IP Addresses. Many Webmasters haven’t heard of the term Class C and thus naturally overlook this.

In this article, I’m going to explain the basics of what a Class C IP is, why it’s an important factor in SEO – both on-page and off-page.

Class C IP

In layman terms, an IP address consists of 4 parts:

We call the first 3 parts the Class C of an IP. So for example:

• 123.456.789.111 and 123.456.789.222 are in the same Class C
• 123.456.123.111 and 123.456.789.222 are in two different Class C’s

Two websites that are hosted on the same Class C IP range will probably be stored on servers in the same room or near each other and managed by the same hosting company. Certain hosts who promote themselves by offering “SEO Hosting” will generally have access to multiple Class C addresses and be able to supply you with multiple Class C addresses at a small cost – A quick search on Google will yield many results.

Class C and Off-Page SEO

Search Engines track the number of IP addresses a website has been through and although sometimes it’s necessary, too many changes will likely be detrimental because it will give the impression of illegal sites (that go down and get banned by their host 1 week and come back the next via another host). Yahoo Site Explorer display various statistics about your site which include “Known Hosts on This Site” which can give you an idea of how many host’s a site has been through: In terms of Backlinks, having 10’000 links from the same Class C IP has minimum weight and 50 links of a similar quality from different IP addresses are more valuable to the Search Engines. For sites you wish to rank in the UK, you should concentrate more on building links from Class C IP’s that are located in the UK (of course, if the TLD is .uk, it will help but that’s another topic for another time .

Class C and On-Page SEO

What is there to analyse in terms of on-page? With regards to links from your site – If, 90% (for example) of links point to the same site/IP, this won’t be seen as quality content for users and will seem like spam to the search engines. You can use Bing’s search command “LinkFromDomain” so see a list of links from your site: Again, looking at the geo location side, if you want a site to rank in the UK then your site should be primarily aimed at UK users and so, linking out to Class C’s located in other parts of the world should be kept to a minimum.

Class C SEO Tool

I’ve decided to put together a quick tool for users to find the Class C of multiple Domain Names and should be ready in the next 2 weeks!