Make Apache Web Server Listen on Two Different Ports

1. Overview

The server in web applications frequently has to listen on more than one TCP port. The application may perform better and be more flexible as a result of this.

We’ll learn how to set up the Apache web server to listen on two separate ports in this article.

2. Modify Port Config File

The port configuration file, /etc/apache2/ports.conf, must first be updated.

Listen 80

<IfModulessl_module>
    ...
</IfModule>

The Listen 80 declaration is visible, indicating that port 80 is the application’s default listening port.

To bind the second port to our application, we add a line Listen . For example, for port 8888, we’ll need to add Listen 8888 line:

Listen 80

Listen 8888

<IfModulessl_module>
    ...
</IfModule>

As we can see, our Apache web server now listens on both ports 80 and 8888.

3. Update Virtual Host File

The Virtual Host file must then be configured to listen on the new port as the next step.

The virtual host configurations are kept in the Virtual Host file. The user can manage hostname and port settings for various web pages using this file. It offers the ability to use the web server for various hostnames and ports, in particular.

We only need to add the second port to this file for this lesson.

The file /etc/apache2/sites-enabled/000-default.conf contains the configuration for the Virtual Host. Let’s examine the file to see the default configurations:

<VirtualHost *:80>
    ...
</VirtualHost>

 vim: syntax=apache ts=4 sw=4 sts=4 sr noet

vim: syntax=apache ts=4 sw=4 sts=4 sr noet

At the top, there is a statement, which means that our application uses a virtual host on port 80.

To make our page work for both ports 80 and 8888, we need to add *:8888 after port 80:

<VirtualHost *:80 *:8888>
    ...
</VirtualHost>

 vim: syntax=apache ts=4 sw=4 sts=4 sr noet

As a result, the Virtual Host file now contains both listened ports.

4. Reload the Apache Service

We changed the configuration files in the aforementioned sections to make our server listen on the second port.

So now, we need to make the server apply these settings. For that, we should restart the Apache service:

    
      sudo service apache2 restart

We may need to enter the password to be able to proceed because this command requires sudo access.

5. Verify Everything Works

It’s time to verify that everything functions as intended when the server has been rebooted. The Apache service should now be visible as listening on the two ports.

The netstat command, a fantastic tool for displaying network connection information, can be used for that:

    
      sudo netstat -nltp | grep apache
      tcp6       ...      ...       :::8888         ...        LISTEN      1907/apache2        
      tcp6       ...      ...       :::80           ...        LISTEN      1907/apache2

We used the following settings when running netstat:

-l shows listening ports
-n displays the port numbers
-t filters for TCP ports only
-p shows the process names, which helps us identify the Apache process

Apache is listening on two ports, as we can see. Port 8888 is shown on the top line, and port 80 is shown on the bottom line.

FAQs

Can I add more than two ports to Apache?

Yes, you can. Simply add additional `Listen` statements in the port configuration file.

Does changing the listening ports affect existing web applications?

No, existing web applications should remain unaffected by adding new listening ports.

How do I troubleshoot if Apache fails to restart after configuration changes?

Check the Apache error logs for any specific error messages that can guide you in troubleshooting.

Can I use non-numeric values for ports, like “http” instead of a number?

No, ports must be numeric values. “http” is not a valid port specification.

Is it necessary to restart Apache after modifying the port configuration?

Yes, restarting the Apache service is necessary for the changes to take effect.

Can I configure different virtual hosts for each listening port?

Yes, you can have distinct virtual host configurations for each port.

Are there security considerations when adding new listening ports?

Ensure that firewall settings are adjusted to allow traffic on the new ports, and monitor for any unexpected behavior.

Can I use ports below 1024 for Apache?

Ports below 1024 are considered privileged, and running Apache on these ports may require additional permissions.

How can I check if a specific port is open and reachable?

Utilize tools like `telnet` or `nc` to check if a port is open and reachable from a client machine.

What should I do if I encounter “Address already in use” when adding a new port?

This error indicates that the port is already in use by another application. Choose a different port or identify and stop the conflicting application.

In conclusion

We learned how to configure the Apache server to listen on two separate ports in this post.