How to redirect an HTTP connection to HTTPS in Apache webserver

HTTP connections can be redirected to HTTPS using the apache mod_rewrite module. Mod_rewrite should be available in every apache installation.

Apache HTTP to HTTPS Redirect

Create a file with the name .htaccess in the website root directory which contains the following lines:

RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}

If you use ISPConfig 3, you can add these lines also in the apache directives field of the website settings form instead of adding them to a .htaccess file. Or use the HTTP to HTTPS redirect option on the redirect tab of the site. But the approach with the .htaccess file will work on ISPConfig as well.