ServerBuddies Support Blog

Webmin behaves differently depending on the operating system or Linux distribution that you have installed, and the particular version that you are running.

The correct OS is always automatically detected at installation time or provided by the installer, but it is quite possible that your system may be upgraded during the lifetime of the system.

If this happens, Webmin will not automatically detect the upgrade - you must tell it by following these steps :

1. Click on the Operating System and Environment icon on the module’s main page.
2. Select your Unix vendor and version from the New operating system list.
3. Hit the Save button to have Webmin start using it.

The operating system and version detected at installation time determines the default values for module configurations, as each flavor of Unix uses different locations and formats for the various config files that Webmin manages.

However, changing your OS by following the steps above will not adjust any of these configuration settings. Instead, it will just determine which ones are used for modules installed in future. Usually this is not a problem, as most OS upgrades will not change the locations of files and programs.

However, some modules may need to be manually configured after an upgrade - for example, you may need to change the print system used by the Printer Administration module if the old OS version used LPRng and the new version uses CUPS.

Webmin error message Unable to identify operating system

When installing the Webmin RPM, I get the error message Unable to identify operating system.

This happens if Webmin cannot identify your OS by looking at your /etc/issue file, possibly because it has been changed from the default contents. The best solution is to install the .tar.gz version of Webmin, which asks for the OS name and version manually.

How to limit server resource allocation to system users

The file /etc/security/limits.conf, contains the various limits for users or groups that can be set. In this case, we set the max locked-in-memory address space, memlock (KB). For example, if user bob needed to have a hard limit of 512 MB of RAM, then add in the following line:

Where domain can be

The “type” can have following two values

The “item” can be one of the following values

Network Information System

On of the important use for NIS is to keep vital data such as user account information (e.g. /etc/hosts, /etc/passwd and /etc/group files) synchronized between all hosts.Let us see how we can configure NIS. NIS is a server-client based architecture. There will be a NIS server and then a NIS client. Let us see how we can configure this both

NIS SERVER:

You must first check whether we have a package called ypserv installed in the server. Once the package is installed then start the service called ypserv. Then you must give a NIS domain name for the server which can be provided

Also you can verify your domain name by just typing “nisdomainname:. Also there should be entry in the file /etc/sysconfig/network like this

The next thing you have to do is you have to share the directory where you user accounts are residing. For example lets suppose that you creat a directory called home1 and you want to the NIS users home directory to be home1 then you can do this like,

where test is the NIS user. Once created you have to export this file through nfs.This can be done like this

by putting entries in the /etc/exports file

Once you have put these entries make sure that the services portmap and nfs are started. Once you have done this we have to make the yp file which can be done like this,

Then restart the ypserv services. Also make sure that the service called yppasswdd is also turned on These are the things that has to be done on the server side.

NIS CLIENT: To make a NIS client check whether the package ypbind is installed in the system. Also check that the service called autofs is also turned on.Then there are two important files that we need to consider that is /etc/auto.master and /etc/auto.misc . The service autofs is used so that the directory that we use or shared through nfs is automatically mounted and also see that when a nisuser login then a directory is also automatically created.In /etc/auto.master file give the entries like this

Then an entry about our nis server should be given auto.misc like this

Also you have to tell the client which is the NIS server which can be told like this. In the command prompt

Select NIS then select next then give the nisdomain name and the ip of the NIS server and then exit. If it listenx to the NIS server then there wil be no errors shown. now if everything goes well you should be able to login as test in all the NIS clients.