mod rewrite IP to URL

Yes, but you're quite close.

> Is what I'm asking about possible with mod_rewrite?

Five examples:

In example.com/.htaccess:

 RewriteCond %{HTTP_HOST} ^123\.123\.123\.123
RewriteRule ^sub_dir/(.*)$ http://www.example.com/sub_dir/$1 [R=301,L]

In example.com/sub_dir/.htaccess:

 RewriteCond %{HTTP_HOST} ^123\.123\.123\.123
RewriteRule (.*) http://www.example.com/sub_dir/$1 [R=301,L]

In example.com/.htaccess:

 RewriteCond %{HTTP_HOST} ^123\.123\.123\.123
RewriteRule (.*) http://www.example.com/$1 [R=301,L]

In example.com/.htaccess:

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

In example.com/httpd.conf

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

In example.com/httpd.conf

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

For more information, see the documents cited in our forum charter [webmasterworld.com] and the tutorials in the Apache forum section of the WebmasterWorld library [webmasterworld.com].

Jim

RewriteCond %{HTTP_HOST} ^123\.123\.123\.123
RewriteRule (.*) http://www.example.com/sub_dir/$1 [R=301,L]

...was EXACTLY what I needed. It worked perfectly, a quick server header check shows a 301 for the IP version of the URL, and hopefully will keep Google smiling down on me. :-)

Dave