Redirect non-www domain but not IP's

I am looking for a way to rewrite non-www-domains to www-domains, while at the same time not redirecting direct IP-requests.

I have multiple sites on the same server - that is: a default (virtual)host and one VirtualHost with a ServerName and multiple ServerAlias'es, which work perfectly. I prefer the domainnames to start with "www". So I have hacked the following code together, which works great:

RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteRule ^ http://www.%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

It doesn't handle https, b开发者_运维问答ut the biggest problem is that requests to the server-IP are also rewritten from eg. "123.45.67.8" to "www.123.45.67.8". I could add the line below to solve that:

RewriteCond %{HTTP_HOST} !^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$

... but it is it effective? And what about IPv6?

Being no mod_rewrite-wiz, I have been trying to figure out how other people have solved this problem, but with no luck.

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That's because your condition is only checking if it starts with www, try this instead (I left the optional https code):

RewriteCond %{HTTP_HOST} ^(yourdomain|thisdomain|thatdomain)\.com
#RewriteCond %{HTTPS} =on
#RewriteRule .* https://www.%{SERVER_NAME}%{REQUEST_URI} [R,L]
RewriteRule .* http://www.%{SERVER_NAME}%{REQUEST_URI} [R,L]