Link Blocks

[LeeMiller]

Sorry, perhaps a noob question.

In relation to site explorer, have also searched and unable to find any information, wondered if anyone could advise as to what "Linking C Blocks" are? Found under the "Compare Link Metrics" tab.

Thanks in advance.

Lee

[gfiorelli1]

There's an old great answer to your question in the Search Engine Forum. I copy it here:

A "C" Block address is based on your IP. In general, webhosts are given a different class C, so if you have a different C block, you are usually talking about two different webhosts.

I'm talking about the actual hardware owners here, of course. If two resellers of the same host sell you two hosting accounts, there is a good chance they are both on the same Class C.

Google assumes that sites hosted by two different hosts are probably separate, and therefore links between sites hosted on them are more likely to be from different people. There are problems with that assumption, but it's one of the things they look at anyway (gotta look at something).

Let's say you had an account with a shared IP address. So, for example, you had two sites that both used 192.168.5.1 as an IP. Google would tend to assume that these two sites are related, since they are on the same IP. This can be an issue with free or cheap hosts, which may have thousands of websites hosted on the same shared IP. You would normally try to avoid this if you had multiple sites that were likely to link to each other.

Now let's say that you got yourself 2 different (static) IP - your host would probably give you 192.168.5.2 and 192.168.5.3, in this example. Well these are two different IP's all right, but they are right next to each other, aren't they? Google would also likely consider these to be related.

But what if you hosted with another site across town? Perhaps they would be assigned a group of IP's to hand out that look like 192.168.122.XXX. Well, that 122 now indicates a different ISP, and therefore two sites hosted at this level are more likely to be considered unrelated.

To make a long story short:

192.168.006.001

is a standard, fully qualified IP address. The blocks in this case are:

AAA.BBB.CCC.001-254

That's not a Typo - Class D and E look totally different. The last 3 digits are actually called the Rest Field

So these are within the same class

192.168.222.111
192.168.222.230

And these are different Class C IP's:

192.167.111.233
192.168.222.233

I quote just part of the post, as part of is related to a specific issue. You can read it here: http://forums.searchenginewatch.com/showthread.php?t=14838

[Netboost]

Gian is pretty much right. Linking C blocks is a useful metric to know. Websites on the same C-block IP address are likely owned by the same person/company and will give less weight.

For best results your linking c-blocks should be as close to your linking root domains as possible. Diversity is the key. Otherwise you could just buy 1000 root domains, host them on the same server space for very little cost and dominate the search results.

[LeeMiller]

Ah, many thanks to you both

would I be right in assuming links from the same C Block would pass less juice or would none be passed?

Also just to clarify, the figure in site explorer shows 192 what is this telling me? Not sure if this is what it is describing but the figure for "Total Linking Root Domains" is 240.

lol sorry, so many questions

[RobertFisher]

What a well presented, excellent answer. Are the A blocks and B blocks ever relevant in a way similar to that of the C block being same host?

Thanks Gianluca

[gfiorelli1]

I would not think to blocks as a discriminant in passing more or less link juice, simply I will take them into account as an ever better way for Google to understand if a site is really "popular" or not.

1. No links = site totally ignored by the users
2. Links but poor unique root domains diversification = poor popularity and maybe spam based links
3. Links and great number of unique root domains but por C-Blocks diversification = good popularity, but maybe based on sites's network
4. Links and great number of unique root domains and good diversification of C-Block = good popularity and more probably based on natural link building (even though manipulative actions cannot be excluded)

There's then the case of a site that has few links from a not too big unique domains names on different C-Blocks. I saw cases that this kind of sites can compete well against the third case I've listed above.

About your last question, just with your words i cannot understand it well. May you add a snapshot of what are you seeing?

[gfiorelli1]

On a SEO perspective, right now they do not seems correlated to better rankings. Honestly the best person to answer your question should be Rand himself, as he is surely more expert than me on this "correlation"  thing

[AlanMosley]

I doubt it, there are 254 ips in a c-block, but there is 65,000 in a B and 16,000,000 in a A.

Now considereing that 1 ip number can have thousonds of websites, such as discountASP hosting. the chance of gettiing a link from the same B or A are very high, exspecialy in teh same city.

I believe that the whole c-block thnk is over blown for these reasons

discountASP is a huge hosting company, yet they run all website on one IP number.
You can in theroy have 14 billion ip numbers on your network using nat translations with only one external ip number, using host headers the number is infinate.

So while I beleve that SE's take c-blocks into account, i dont think its too much of a problem unless you have a high percentage.

I have this problem because i build and host sites myself. so its of limited use my putting my link on each one, infact it could be harmfull.

I wonder if google takes this in to account, that many like me that develop websites and host them have this problem.

[LeeMiller]

no problem, tbh I struggled a bit writing the question :)) See attached though, much appreciated.

GqJy8.jpg

[gfiorelli1]

Ok, better now

Well, it seems a good link profile:

you have 240 linking root domain and 192 of them are from different c-blocks and of those 240 root domains 205 are followed.