Managing Linux Through A Browser

Red Hat comes with easy-to-use and powerful graphical administration tools

Now that you’ve probably gone through all the configuration files and set up your Linux server, we’ll show you some easy ways of doing things. Red Hat comes with a few graphical tools for easing your admin issues.

WebMin: An HTML-based remote admin tool

WebMin is an HTML based tool that lets you remotely administer a Red Hat Linux server. Just open up a browser on any machine, and configure and manage your server from almost anywhere.

Setting WebMin is very simple. In the PCQ CD-ROM, go to the PCQUPDT directory and run the pcqupdt script file. If you haven’t previously run this script, it will upgrade many key files. Then, the script will ask you whether you wish to install the Remote Admin for Linux tool (WebMin). Answer Yes here, and you’ll need to answer few more questions for the setup to complete. You’ll first be asked the port number on which the tool is to be made available. You can safely accept the default of 10000. Next, you’ll need to enter a password for the account to access the tool.

You can access WebMin using a Web browser by going to the URL http://server_ip_address:10000. The browser will prompt you for a login and password. Enter admin and the password you had given earlier. After authentication, the WebMin main index comes up. This lists all the modules that you can use to control your Linux Server.

The first module is WebMin Users. From here, you can create new WebMin users, and select the modules to be made available to them. For example you could create a user who has access to only disk related activities like file and directory shares, and disk quotas. Users can be edited, or deleted from here.

If you need to run certain commands periodically, you can schedule these jobs as Cron Jobs. Cron is a UNIX tool that runs some commands at regular intervals. Instead of configuring this tool at the command line, you can use WebMin to schedule the jobs. The Scheduled Cron Jobs module contains a list of all jobs that have been created and allows you to add, edit or remove them and create new jobs. To create a new job, click on the hyperlink, which takes you to a configuration page. Here you need to select the user to whom the job has to be assigned, the actual command you wish to execute and any parameters you wish to pass to this command. You then set the execution time by selecting the minutes, hours, days, months and/or the weekdays.

Next comes the module for the BIND DNS Server, which allows you to manage domain names on your machine. You can set both forward domains (which map names like abc.com to IP addresses like 213.213.65.34) and reverse domains (that map IP to names). The page allows you to create primary domains by specifying the domain name or address, depending on whether you want a forward or reverse lookup domain. You also have to specify an e-mail address of the person who handles this domain, the nameserver (the name of the machine) and an optional filename for storing this information. Similarly, secondary domains can also be created, except that they need the address of at least one primary domain nameservers. This page even allows you to restart the nameserver by just pressing a button.

The Internet Service and Protocols module lets you configure services like FTP, Telnet, gopher, and a host of others. You can set the port, protocol, the user, and the group to execute the service and other details like the program to run, its parameters, and so on. You can also add and edit new services. The page also has a button to restart Inetd.

The Bootup and Shutdown Actions option lets you view and configure all the services and programs that run on system startup and shutdown. The page shows you a list of all these. You can simply click on any one to configure it. You can create new actions similarly by specifying the name and the commands to run. You can also select the Runlevels for starting and stopping the action.

The next module, Disk and Network File Systems, let you mount local disks, CD-ROMs, file shares, and even virtual memory. Before being able to access any file system, say on a CD-ROM or a network shared folder under Linux, they have to mounted. This tool simplifies the process. It allows you to choose the kind of system you want to mount and select other parameters, like whether to mount this system on system startup, the kind of device, that is, SCSI, CD-ROM, floppy or IDE. You can mount many different filesystems, like FAT, VFAT, HPFS, and many UNIX variants.

The PPP Usernames and Passwords allow you to create users who can connect to the server using PPP logon. This is useful when you’re setting up your server as a PPP dial-in for accessing the Internet or the intranet. You can manually or automatically create users and also change or delete a PPP user.

The Running Processes is a very powerful module. It lists all the processes currently running on the server. You can search for a particular process based on the owner, filesystem, CPU usage, file usage, or by name matching. Simply click on any process to see details. These details include the process, PID, the parent, and sub processes if any, the CPU, memory, and size. Finally, you can send the process any kind of signal. For example, you could simply KILL an errant process by sending an appropriate signal.

File Shares for Windows Networking lets you create Windows NT-type shares using the Samba server. Users who login to your machine using a Windows client, will be able to use the folders as if they were logged in to a Windows NT domain. You can add shares by selecting the directory to share and the user access rights.

Another useful module is Installed Packages. This allows you to view, category-wise, the packages that have been installed on the server, like Base, Networking, Utilities, Games, and others. Click on any category to see packages installed in it. You can also search for a particular package. You can uninstall any package or view the file(s) that make it up. The module also allows you to install a new package by choosing the RPM package from a local disk, an HTTP, or FTP URL.

The Users and Groups module lets you quickly and easily setup new users or groups, and manage them. You just need to set the full name, the shell, a path to his home directory, and the groups the user belongs to. On saving the options, a home directory is created for the user and the access rights are set.

And finally the module to manage WebMin itself, WebMin Configuration. This lets you set up IP addresses or Host names, which will be the only ones able to use the WebMin interface. This is to prevent unauthorized users, on the Internet, from being able to manage your entire server, if your server is connected to it, and they guess the password. You can also change the IP address and Port on which WebMin listens for requests. Logging options for the Web server can also be specified here. You can also add or remove individual modules from here. For adding a module, you need to specify the location of a .WBM file (which contains the modules), on your disk, or a URL.

The Control Panel: An X-based tool

The Red Hat Linux control Panel is an X-based tool, installed if you’ve chosen to install X windows too. When you start X as root on your server, you’ll see the control panel docked on a side of your desktop, which allows you to view and manage many options using graphical tools.

First comes the User Configuration. This lets the administrator create, edit, or remove users and groups from the server. To add a new user (or group), fill in the required details. Everything else is done automatically. To view or edit one, double click the entry and all the details are displayed. Except for the username, all other details can be edited.

The RunLevel Manager lets you manage the processes that execute in different Runlevels. These are used to setup multi-purpose machines. You can configure certain processes to run in a server runlevel, and others in a user runlevel. A machine can have upto 7 runlevels and managing them all becomes very simple using this tool.

The Print System Manager lists all the print queues configured on your machine and allows you add and modify them. To add a printer, select Add and the printer type. The type can be a local printer, a remote UNIX (or TCP/IP network) printer, or a printer configured on an NT or Netware server. There is a detailed article that explains this job.

The Network Configurator manages settings like the domain name, host name, and nameservers. The HOSTS file can be modified by using the Hosts page to set the IP address, name and nicknames if any. The Interfaces page lets you create new interfaces, like PPP, SLIP and others, and configure them. And finally, the Routing page allows setting of IP packet forwarding and the default gateway.

The File System manager lets you view and configure the file systems. You can mount, unmount, format, view information, or edit the file system parameters using a simple dialog box. The parameters include the system name, like /dev/cdrom, read/write options, whether it is to be mounted on startup, allow programs to be executed, and others.

The Control panel also has other tools for configuring Apache, installing or removing packages, and changing the date or time.

We kept this article at the end to make you aware of the actual stuff that goes in, so that if you’re ever in a situation where you do not have access to these, you can still get your work done. You can now, of course, use these tools to do a lot of the jobs and may not like to go back to the dark, dreary world of command-line configurations.