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The solution we’re proposing is to do 301 redirects to a single “standard” version of the link. Lucky you,

the functionality is already there! The

fix_category_product_url()

function from

url_redirect

.inc.php

already takes care to redirect any errant or outdated link to its “proper” version, in case the

URL isn’t already what it should be.

Trying to load any of the two previously mentioned links would simply redirect you to:

http://seophp.example.com/Products/SEO-Toolbox-C6/Link-Juice-P31.html

Dealing with Multiple Domain Names Properly

Though it’s less popular these days, some people desire to have multiple domain names pointing to the

same site. For example, say you have three domain names:

www.example.com

www.example.org

www.example.net

The problem is that, especially if you market all three domains, people are free to link to any of these

domains. That’s a major duplicate content issue. You must pick a “standard” domain and permanently

redirect the other domains to that domain.

Let’s pick

www.example.com

. This is how to do it with mod_rewrite:

RewriteEngine on

RewriteCond %{HTTP_HOST} !^www\.example\.com

RewriteRule ^(.*)$ http://www.example.com/$1 [R=301,L]

Done! Now everything will get redirected to

www.example.com

. Let’s analyze the rules in detail.

This is the first time you’re using

RewriteCond

. You use

RewriteCond

to place a condition for the

rule that follows. In this case, you’re interested in verifying that the site has been accessed through

www.example.com

. Take another look at the

RewriteCond

line:

RewriteCond %{HTTP_HOST} !^www\.example\.com

This line specifies a condition that is true when the host name (

HTTP_HOST

) is not (

!

)

www.example

.com

. The rewrite rule captures the entire query string of the original URL, as

(.*)

, and passes it to

http://www.example.com

, doing a 301 redirect to the new location. This way, for example, a query

to

http://www.example.org?query=string

would be 301 redirected to

http://www.example

.com?query=string

.

Using Redirects to Change Domain Names

Sometimes you

have

to change your domain name. Usually this happens in M&A (mergers and acquisi-

tions) cases. Although undesirable, there is a right way to do this, and many wrong ones. Typically both

domains need to point to the same web site now that the merger occurred. The

worst

thing you can do is

simply point both domains to the same content via DNS. This will result in search engines not knowing

90

Chapter 4: Content Relocation and HTTP Status Codes

c04.qxd:c04 10:40 90

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