RewriteEngine On

RewriteCond %{SERVER_PORT} =80
RewriteCond %{HTTP_HOST} ^mail(\.[^.]+)+$
RewriteRule .* http://%{HTTP_HOST}:2095 [R=301,L]

RewriteCond %{SERVER_PORT} =443
RewriteCond %{HTTP_HOST} ^mail(\.[^.]+)+$
RewriteRule .* https://%{HTTP_HOST}:2096 [R=301,L]