Redirect non-www to www in .htaccess

Question

I have this in my .htaccess file:

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

but whenever I

Answer 1

If possible, add this to the main Apache configuration file. It is a lighter-weight solution, less processing required.

        ServerName example.com
        Redirect permanent / http://www.example.com/


   ServerAdmin me@example.com
   ServerName www.example.com
   DocumentRoot /var/www/example
   .
   .
   . etc

So, the separate VirtualHost for "example.com" captures those requests and then permanently redirects them to your main VirtualHost. So there's no REGEX parsing with every request, and your client browsers will cache the redirect so they'll never (or rarely) request the "wrong" url again, saving you on server load.

Note, the trailing slash in Redirect permanent / http://www.example.com/. Without it, a redirect from example.com/asdf would redirect to http://www.example.comasdf instead of http://www.example.com/asdf.