RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_URI} !components/
RewriteCond %{HTTP_HOST} ^([^\.]+)\.oxfamnovib\.net [NC]
RewriteCond %1 !^(www|foo|mail)$ [NC]
RewriteRule ^(.*) http://foo.domain.net/index.php?webspace_unix_name=%1$1 [P,L]