How to Configure Apache as Reverse Proxy (Ubuntu, Cloud Server)

Normally these days we use Nginx as reverse proxy. Like, in an old guide we have shown how to use Nginx reverse proxy to add an IPv6 address to IPv4 only dedicated server. Also we provided configuration of such for HSTS website. We actually can use Apache web server as reverse proxy. Here is How to Configure Apache as Reverse Proxy on Single Cloud Server Instance Running Ubuntu 16.04 For IPv4. We will use some cloud server like VPSDime $7 per month 6 GB OpenVZ instance for this work. For very small need, we can use 1GB RAM at 1 Euro Per Month Aruba Cloud VMWare instance. We will set up Apache as a basic reverse proxy using the  mod_proxy extension to redirect the incoming connections to one or several backend servers.

Required Modules to Configure Apache as Reverse Proxy

The modules that are needed to use Apache as a reverse proxy includes :

1. mod_proxy : the core proxy module Apache module for redirecting connections
2. mod_proxy_http : adds support for proxying HTTP and HTTPS connections.
3. mod_proxy_balancer : adds load balancing features.
4. mod_lbmethod_byrequests : adds load balancing features.
5. mod_proxy_ftp : This handles fetching documents with FTP.
6. mod_proxy_connect : This handles the CONNECT method for secure tunnelling.
7. mod_proxy_ajp : This handles the AJP protocol for Tomcat like backend servers.
8. mod_proxy_html:  This rewrites HTML links into a proxy’s address space.
9. mod_xml2enc : This supports internationalisation behalf of mod_proxy_html.
10. mod_headers: This modifies HTTP request and response headers.
11. mod_deflate: Negotiates compression with clients and backends.
12. mod_cache : To enable caching.
13. mod_disk_cache : To enable caching.
14. mod_mem_cache : To enable caching.

How to Configure Apache as Reverse Proxy

First update and upgrade :

Now, we will install Apache on our server :

Once Apache has been installed, we need to start the Apache service, configure it to start automatically restart on reboot. Open :

We have to install mod_proxy and dependencies :

Run the below command to get the list of available modules:

We need to run commands to enable the modules we need, one by one :

Apache default configuration file is usually 000-default.conf, we can create our own virtual host file at /etc/apache2/sites-available location :

Now, add something like this on that /etc/apache2/sites-available/proxy-http file :

Save and close the file. Enable new virtual host file:

We may also need to direct Apache to listen on port 8080. “May”, as it depends. That can be done by editing the ports.conf file:

Directive will be :

If you change, you need to restart :

In the above change of port case, http://i.p.a.d.d.r.e.ss:80 will show the application which is running on http://i.p.a.d.d.r.e.ss:8080. If we want to enable SSL support, then we will need to enable the SSL module first.

Next, you will need to use Let’s Encrypt certificate in the way we have shown for Nginx in different guide.
We can copy all the certificate files to the /etc/apache2/ssl directory. We will create new virtual host file named proxy-https :

Here is example config :

Save and close the file. Enable new virtual host file:

There is huge documentation on Apache’s site :

We provided quite basic examples on how to configure Apache as reverse proxy, but possibly that is the critical part.