Question

I’m trying to find a generic enough modrewrite rule that will acomplish following:

Redirect anyHost.anyTld to http://www.anyHost.anyTld
Not mess with any other subdomains, for examle other.anyHost.anyTLD should be left alone
Can you help? Does this slow down server too much?

Answer 1

This should work:

RewriteCond %{HTTP_HOST} ^([^.]+\.[^.]+)$ [NC]
RewriteRule ^(.*)$ http://www.%1/$1 [R=301,L]

I’m no expert on the speed (or lack thereof) of mod_rewrite, but I don’t think you would notice any impact on speed.