Apache Reverse Proxy Configuration For Ubuntu/Debian Linux

Last updated on August 10th, 2020 at 03:05 am

Apache Reverse Proxy allows you to run one or more backend servers behind a proxy server, without exposing them publicly. It also helps with load balancing. Here’s Apache Reverse Proxy Configuration for Ubuntu/Debian Linux.

 

Apache Reverse Proxy Configuration Step By Step

Here’s a step by step Apache Reverse Proxy Configuration for Ubuntu/Debian Linux systems.

 

1. Install Required Apache modules

We require 4 Apache modules to configure Apache reverse proxy – mod_proxy, mod_proxy_http, mod_proxy_balancer, mod_lbmethod_byrequests

• mod_proxy is the main proxy module that redirects requests and allows Apache to act as gateway to backend servers
• mod_proxy_http allows support for proxying HTTP requests
• mod_proxy_balancer and mod_lbmethod_byrequests add load balancing capabilities to Apache web server.

Open terminal and run the following commands to install pre-requisite Apache modules.

$ sudo a2enmod proxy
$ sudo a2enmod proxy_http
$ sudo a2enmod proxy_balancer
$ sudo a2enmod lbmethod_byrequests

Bonus Read : How to Install & Configure mod_pagespeed with Apache

 

2. Restart Apache Server

Restart Apache Server to apply changes

$ sudo service apache2 restart

 

3. Setup backend server

We will install & setup flask server to run on port 8080 as a backend server.

$ sudo apt-get update
$ sudo apt-get -y install python3-pip
$ sudo pip3 install flask

Flask comes with a readymade ~/backend.py file that returns “Hello World” on requesting home page.

from flask import Flask
app = Flask(__name__)

@app.route('/')
def home():
    return 'Hello world!'

 

Bonus Read : How to Check if mod_expires is enabled

 

We will run flask server

$ FLASK_APP=~/backend.py flask run --port=8080 >/dev/null 2>&1 &

You can test this server by running curl command

$ curl http://127.0.0.1:8080/

You will see the output as Hello World!

 

4. Update Apache Configuration

We need to modify Apache’s default configuration file to enable reverse proxy. Open Apache configuration in text editor

$ sudo vi /etc/apache2/sites-available/000-default.conf

Add the following lines to VirtualHost tag in Apache configuration file.

        ProxyPreserveHost On
        ProxyPass / http://127.0.0.1:8080/
        ProxyPassReverse / http://127.0.0.1:8080/

Let’s look at the 3 directives.

• ProxyPreserveHost causes Apache to preserve original host header and pass it to back-end server.
• ProxyPass is the main proxy directive which states that everything under root (/) should be directed to back-end server. If Apache gets request for /example, then it will send the request to http://your_backend_server/example
• ProxyPassReverse tells Apache to modify response header in the response received from back-end server. This is useful in case the back-end server returns a location redirect response, then the client will be redirected to Apache proxy server, instead of back-end server.

<VirtualHost *:80>
...
ProxyPreserveHost On
ProxyPass / http://127.0.0.1:8080/
ProxyPassReverse / http://127.0.0.1:8080/
...
</VirtualHost>

Bonus Read : How to Enable mod_headers in Apache

 

5. Restart Apache Server

Restart Apache Server to apply changes

$ sudo service apache2 restart

 

Hopefully, the above Apache reverse proxy configuration will help you setup proxy server for your website.

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