SEO behind the scenes – www versus non-www URLs
I’m ‘bout to get geeky on you.
It’s funny when you think you know everything you need to know about an SEO issue. For example, I thought I had www versus non www URL problems all figured out. If you’re not familiar with the problem, I’ll give you some background. If you already know what the problem is with www versus non-www URLs and the standard SEO solution, skip the background and go straight to the meat.
Background – what’s the problem with www versus non-www URL?
There are two common problems.
1. Your site loads perfectly whether you use the www or not
Ex: http://www.yourdomain.com loads the same content as http://yourdomain.com
This causes problems because it splits your pagerank when some people link to your www-version and others link to your non-www version. Split pagerank means lower rankings for both versions of your site.
2. Your site only loads one version, and the other version renders an error.
Ex: You don’t need an example, you know errors are bad.
The standard solution: Pick one and 301 the other. I thought the options were 301, 302 or do nothing.
</background> on to the new stuff
Then the issue came up in the morning meeting with the programmers. They suggested a CNAME solution or a ServerAlias directive.
I’m all “A c-wha?” so I did some research.
The best way to properly associate two different domains versions from a DNS standpoint is to provide the correct Resource Record in the appropriate DNS Zone and follow through with a proper HTTP 301 redirection at the final point of URL resolution.
I think that means do a 301.
Although a CNAME can be used and works from a browser standpoint, without any HTTP redirect it will result in duplicate content available at multiple URLs.
I think that means that even though a CNAME will seem to solve the problem, it actually doesn’t solve the duplicate content problem. What I want to know is whether the pagerank splits. If a site links to one version, does only that version get the pagerank, with none transferred to the other version? It would appear from this explanation that is so.
In regard to the ServerAlias directive, after the proper DNS configuration is made, HTTP level redirection also needs to be done to insure the preferred domain canonicalization is realized.
I think that means the same is true of a ServerAlias directive.
Seems like the bottom line is that you’re going to have to do a 301 to solve the problem correctly for SEO, so just go ahead and do it without worrying about those other solutions.
Could be wrong though; feel free to school me readers.
Suggested reading: http://www.aitechsolutions.net/cname-serveralias-redirection.html