If the content is living on the same server as domainA.com (which it
apparently is in this case), then you don't want to proxy. There is no
need to create an additional HTTP request. You just instruct apache to
grab the file directly. So you want something likeIf this doesn't work, tell us EXACTLY what happens: what do you see in
RewriteCond %{HTTP_HOST} ^domainA.com$
RewriteRule ^(.*)$ /home/user/public_html/siteA/$1
the browser, error_log, and access_log?