Redirecting non www to www ONLY for domain, subdomain without www

Question

How to set htaccess to such examples in a Wordpress Multisite:

• domain.com - redirect to - www.domain.com
• sudomain.domain.com - no redirect

I have a Error 310 (net::ERR_TOO_MANY_REDIRECTS) when my .htaccess file looks like this:

RewriteEngine On 
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{HTTP_HOST} !^www.
RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [R=301,L]

# add a trailing slash to /wp-admin
RewriteRule ^wp-admin$ wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^(wp-(content|admin|includes).*) wp/$1 [L]
RewriteRule ^(.*\.php)$ wp/$1 [L]
RewriteRule . index.php [L]

Answer 1

Try:

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

Answer 2

I think you only need to ask explicit for %{HTTP_HOST} to be domain.com. All implicit conditions like »does %{HTTP_HOST} NOT start with www« will effect all subdomains too. So this should work for your case

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

RewriteRule ^index\.php$ - [L]

# add a trailing slash to /wp-admin
RewriteRule ^wp-admin$ wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^(wp-(content|admin|includes).*) wp/$1 [L]
RewriteRule ^(.*\.php)$ wp/$1 [L]
RewriteRule . index.php [L]

Make sure, that the constant DOMAIN_CURRENT_SITE and the domain attribute (in network settings) of your root blog is set to www.domain.com. The NOBLOGREDIRECT constant might also be helpful for your purposes.

Answer 3

You don't need to add any codes in htaccess file. There is very easy solution to this. In the 'Network Admin -> Settings -> Domains' page, add both the www. and non-www. versions of the domain, select the box of 'primary' for if you want to mainly use for www. or non-www. and both will be assigned to the website.