example.com/mcp.php?i=main&mode=frontinstead of modifying files? Just write a announcement in your internal moderator board and tell them to use that link in a separate browser window or tab ...
apachewith the module
.htaccess. See https://httpd.apache.org/docs/current/m ... pires.html for a documentation, and for sure you'll find a lot of examples by using a proper search engine