Add R=permanent as a redirect_type
Under website, subdomain for website and aliasdomain for website, we can select a redirect_type. For Apache servers, currently we can choose no redirect, no flags, R, L, and "R,L". HTTP 301 redirect is a very important (e.g. for SEO) feature but is unfortunately missing. There is a redirect_type="permanent" choice, but it does not work with Apache. The correct setting for Apache should be redirect_type="R=permanent", and the generated config should be:
RewriteEngine on
RewriteCond %{HTTP_HOST} ^domain1.com$ [NC]
RewriteRule ^/(.*)$ http://domain2.com/$1 [R=permanent]