As you would expect, with the help of Webmin, creating a firewall is very simple. And the default Webmin installation comes complete with a firewall module built in, so there is nothing to install (once you have Webmin installed.) All you have to do is point your browser to http://IP_OR_DOMAIN:1000 (Where IP_OR_DOMAIN is the actual IP address or domain hosting your Webmin installation.) If Webmin is installed on your desktop you can point your browser to http://localhost:10000.

Webmin Firewall

Once you are in the Webmin window you will want to click on the Servers link and then click on the Linux Firewall link. The image to the left is the top portion of the configuration screen. This image is showing a default iptables chain that is installed by default in Fedora. As you can see these chain rules are easily modified, moved, appended, and removed.

The Add Rule Window

I want to illustrate how easy it is to add a new rule to the already existing chain. Let’s say you want to add a rule that denies all incoming connections to port 110 (pop3) to your machine. To do this click on the Add Rule button to reveal the Add Rule window (see image to the right.)

The primary configurations to take for this would be:

• Rule Comment: Give the rule a name.
• Action to take: Drop
• Source Address: Any
• Destination Address: 192.168.1. (This will depend upon your needs. If you have a static IP address for the machine enter that.
• Destination Port: 110

Once you have filled this out, click Create Rule and you will be returned to the main window with your rule listed.

Final Steps

Once you have your new rule(s) created you have to scroll down and click the Apply Configuration button (see the image to the left). You will also notice, near the bottom, buttons that allow you to enable your firewall at boot, reset your firewall, and reset to the currently active firewall.

Once you have applied your configuration, if you want to remove a rule you just created you have to go back to the rule list, select the rule you want to delete, and click the Delete Selected button.

It is also important to make sure you have your rules set up in the right order. It is very easy to arrange your rules with the Webmin Firewall Module. Go to the rule listing and click either the up or down arrow the corresponds to the rule you want to move, The rule is then moved one slot up or down (depending upon which arrow you click). But don’t forget to click the Apply Configuration or your move will not stick.

Final Thoughts

If you are looking for a very simple, web-based, solution for creating a firewall the Webmin firewall module might be the answer for you. Not only is it easy to use, you can administer your firewall remotely.

Webmin arrived on the scene in 1997 and pretty much blew away the competition. Webmin is truly a one-stop shop for Linux configuration. It’s modular so you can add and remove modules as they are needed. Webmin can configure your system, servers, networking, hardware, clusters, you name it!

Even though Webmin is a web-based utility, it does not require a server to be installed or running. Webmin contains its own built-in server so you will not need Apache running. Webmin does have to be running in order to log in.

The easiest way to install Webmin is to open up your Add/Remove Software utility, do a search for webmin, and install it. Or you can go to the Webmin Site, download the the appropriate binary and let your package manager do the work for you. If you are wanting to install Webmin on a headless server you can do the following:

• Secure shell to your server
• Download the correct installation file using the wget command.
• Issue the command to install Webmin (such as rpm -ivh webmind-XXX.rpm (where XXX is the release number)

After the installation is complete you may have to start Webmin manually (the rpm installation starts the server for you). To start Webmin you will issue the command:

/etc/rc.d/init.d/webmin start

or

/etc/init.d/webmin start

Once you have started Webmin you log into it with with your browser by pointing it to:

http://IP_OR_DOMAIN:10000

Where IP_OR_DOMAIN is the IP address or the domain Webmin is installed on. If you are using it for local configuration you can point your browser to http://localhost:10000.

Webmin Main Page

As you can see, in the image to the left, the default Webmin page is very easy to navigate.Upon installation one of the first links you should click on this page is the Webmin link in the left navigation. When that menu expands you will see a number of entries, of which one is called Webmin Configuration.

The Webmin Configuration Page

Click on the Webmin Configuration option to reveal a number of possible choices. This section is very important because you will configure access, logging, certificates, categories, and a number of other critical features.

Make sure, however, when you make any changes to Webmin that restart the Webmin server. You can restart Webmin by clicking the Restart Webmin button that is at the bottom of the Webmin Configuration page.

Controlling Webmin

In the same area of the restart button there are a few other important options. If you know you are going to be using Webmin for all of your configuration needs you will want to make sure Webmin starts at boot.

Another important screen to visit, before you jump into various modules, is the Webmin Users screen. In this screen you can define groups and users and their various permissions for the Webmin system. Here you can define what modules a user or group has access to which can be very handy.

Once you get beyond Webmin basic configuration it is time to poke around the various modules. In later articles I will discuss some of the best of the Webmin modules.

Final Thoughts

Webmin is one of the most powerful administration tools available. If you haven’t experienced the power that is Webmin, install it now and see how much power you can have at your fingertips.