Reverse Proxy with mod_proxy

A reverse proxy receives requests and forwards them to another server, then returns the response. Apache does this with the mod_proxy module, commonly used to sit in front of application servers.

Enable the Modules

sudo a2enmod proxy
sudo a2enmod proxy_http
sudo systemctl restart apache2

Basic Forwarding

ProxyPass sends matching requests to a backend; ProxyPassReverse fixes the headers in the response:

<VirtualHost *:80>
    ServerName app.example.com

    ProxyPass / http://127.0.0.1:3000/
    ProxyPassReverse / http://127.0.0.1:3000/
</VirtualHost>

Here a Node or other app runs on port 3000, and Apache exposes it on port 80.

Proxy Only One Path

ProxyPass /api http://127.0.0.1:5000/
ProxyPassReverse /api http://127.0.0.1:5000/

Requests to /api go to the backend, while the rest is served by Apache directly.

Apply Changes

sudo apache2ctl configtest
sudo systemctl reload apache2

A reverse proxy lets Apache handle HTTPS, caching, and routing while your application focuses on its own logic.