Webmin: Linux administration kept simple

One of the biggest problems when a server is needed in a network is the administration. The problem gets more serious if you need to maintain a Linux-based machine and you are a novice in this domain. This can get a little tricky if you don’t come up with a good solution.
 

1. Installation

The best application that can help you in this matter is Webmin. You can get it from http://www.webmin.com/download.html, by selecting your Operating System type. The most common Linux OS support automated installers based on specific packages.

a) For example, if you use a Fedora Core distribution, get the rpm package and it will install by itself (or just login as root in your system and type “yum install webmin”. Fedora will do the rest). The result should be something like this:

In my example, the package was already installed so I just searched for it to see the results. If the ‘install’ argument is passed, yum will search, download and install the program for you, asking only one confirmation.

b) If you use a Debian-based distribution, use the command “apt-get install webmin”. The rest is almost similar.

2. First access on Webmin

To access your administration interface, just open a browser and type http://serverip:10000. This will open the login screen for you.
If this fails the first time, do some troubleshooting: check if the service is running and if it’s accepting connections like shown bellow.



In our case we can see that webmin is running and accepting connections (HTTP traffic flows).

If it’s all ok, you should see the following screen:

Login here with your root account and password to access the administration interface; don’t worry it should be safe if it’s done in your local area network.

3. Web-based administration

As you can see, the first screen will show you a brief server summary regarding resources.

The first thing you should do now is to configure Webmin itself. For accesing any functions, you need to use the cascading menu in the left. Click Webmin and then Webmin Configuration.

Go to IP Access Control and configure the list, as you desire (you can leave the ‘Allow from all addresses’ field check, so you can access you web interface from anywhere; but if the server is connected to the Internet, this can becomes a security risk).

Return to Webmin configuration and go to Authentication. Select the ‘enable password timeouts option’ and block a host for at least 60 seconds after 2 failed logins. This will prevent brute force attacks. Enable session authentication and select a decent timeout for it (5 minutes or so). In addition you can enable a SSL authentication from the Webmin configuration menu. You may need some extra modules to be installed, but Webmin can do that for you.

It’s now safe to use Webmin to your production server.
Please note that you should use a strong root password, with a minimum of 10 characters, containing at least one number and one symbol. Don’t use dictionary-based passwords or sentences; they are the easiest to force in (a password like ihaveaverystrongpassword is not a good idea).

Now you can use the System menu to go and configure the most important parts of your Linux Operating System. You can manage boot/shutdown operations by a couple of clicks and create a username on the system easily by completing a form:

 

Another useful option is the Software Packages menu. You can add, remove and search for any software available for you system. Just have an Internet connection on the server and the application will download and install any program for you, resolving dependencies. You can also do a total system update with only one mouse click.

In the Servers menu, you can choose from a variety of common used Linux services. Note that these are also the recommended applications for different tasks. If a package is not installed on your system (let’s say you select DHCP server), webmin will prompt you for installing it with a message like:

“The DHCP server /usr/sbin/dhcpd could not be found on your system. Maybe it is not installed, or your DHCP module configuration is incorrect.
The ISC DHCPd package can be automatically installed by Webmin. Click here to have it downloaded and installed using YUM.”
You just click it and it will install; then you can configure all the options you want.

Besides Networking and Hardware and their submenus, Webmin offers an interesting feature called Clustering. You can install Webmin on a network of servers linked together and authenticate one which other; after discovering and logging in all servers (automatically) you can perform group commands in your server Cluster. It also includes a heartbeat options to keep the connections alive and learn fast enough if any failure accours.

The “Others” menu holds three interesting options. First is the File manager, where you can add, delete, view or edit any file on your server’s hard disk. Note that this application is based on a Java applet, which is downloaded from the server, so you need Java(TM) Platform installed on your client:



Secondly there is the Upload/Download menu where you can get or put any files from and to your server. This can get very handy if you don’t want to use FTP server software.

Now probably the best option available is the Command shell. This allows you to execute a command as root on the server without being logged via ssh. For example, I wanted to see what are the last system messages and I typed “tail /var/log/messages” and read the output in the web interface as you can see bellow:

Hope this was useful to you!

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