Apache redirect by without URL rewriting

Is there a way I could achieve redirecting to another site, without losing the original URL? So, what we'd want to achieve is to be able to access:
somesite.com/some/url -> someothersite.com/some/url
but we'd like to retain somesite.com/*.
In other words, we'd want to access every URL of someothersite.com via somesite.com.

From serverfault pugmarx

• If you're trying to redirect just a subdirectory of the server, you can use mod_rewrite like this:

  RewriteCond %{REQUEST_URI} /some/url [NC]
  RewriteRule ^(.*)$ other.example.com/$1 [R]
  

  If your trying to show the content of the other site without the user seeing the other url, you'll need both mod_rewrite and mod_proxy

  RewriteCond %{REQUEST_URI} /some/url [NC]
  RewriteRule ^(.*)$ http://other.example.com/$1 [P]
  

  Other configuration steps may be necessary for mod_proxy, depending on your environment.

  Apache's Advanced mod_rewrite Guide may be of benefit.

  From Chris S

• I'd just throw in a file that simply redirects the user with an HTML meta-refresh, or if you want to redirect the user in the most accepted way possible, throw in a 301 redirect rule in an .htaccess file somewhere on the site.

  Example:

  Redirect 301 /some/url http://newsite.com/some/url
  

  Chris S : A meta-refresh would affect the www.example.com page as well; and you'd have to add it to every single page in the whole site for it to work correctly. Adding a redirect in an .htaccess file wouldn't work if there's no default record for example.com.

  Christian Paredes : Hm, good point. I've probably read the question wrong: I see that he wants to redirect EVERY URL from somesite.com to someothersite.com; however, this could use some clarification.

  pugmarx : Added clarification as per your inputs. :)
  From Christian Paredes

• Are you actually looking for a redirect, or to have that other site's content appear under your original URL (more proxying)? I'll assume that the other server is your content and either internal/backend or if public you're aware of the negative SEO implications. If someothersite.com is not your site and content, you probably shouldn't be doing this.

  You'll need to have mod_proxy and mod_rewrite running, which is likely uncommenting the lines mentioning it if not already done.

  Then in the somesite.com config:
  RewriteEngine on
  RewriteRule /some/url(.*) http://someothersite.com/some/url$1 [P,L]

  From Jeremy M