what is the number of repositories for which i can configure YUM?

And are there any chances of instability when using number of repositories with yum?

I am using RHEL5.

And i suspect that i have configure my yum for DAG WIEERS.

How to know that?

You CAN configure yum for as many repos as you wish.

There are issues with mixing too many repos. The general rule of thumb is the base repo(which you MUST have) and one other repo. The problem that often occurs with mixing repos is that two packages may (or may not) have the same name but do not have the same features enabled.

"yum repolist all" will tell you what repos you have configured and which ones are enabled.

I did

yum repolist all

it returned

[root@localhost ~]# yum repolist all
Loading "installonlyn" plugin
Loading "rhnplugin" plugin
This system is not registered with RHN.
RHN support will be disabled.

usage: yum [options] < grouplist, localinstall, groupinfo, localupdate, resolvedep, erase, deplist, groupremove, makecache, upgrade, provides, shell, install, whatprovides, groupinstall, update, groupupdate, info, search, check-update, list, remove, clean, grouperase >

options:
-h, --help show this help message and exit
-t, --tolerant be tolerant of errors
-C run entirely from cache, don't update cache
-c [config file] config file location
-R [minutes] maximum command wait time
-d [debug level] debugging output level
-e [error level] error output level
-y answer yes for all questions
--version show Yum version and exit
--installroot=[path] set install root
--enablerepo=[repo] enable one or more repositories (wildcards allowed)
--disablerepo=[repo] disable one or more repositories (wildcards allowed)
-x [package], --exclude=[package]
exclude package(s) by name or glob
--obsoletes enable obsoletes processing during updates
--noplugins disable Yum plugins
[root@localhost ~]#

What is the problem with my repos?

I dont know much about.

I just followed the instructions on some of the websites which offered configuring yum for repos.

There's no problem with your repos, though without a RHN subscription, you won't get updates through yum. If possible, you should switch to Fedora or CentOS - the former is what releases of Red Hat are based on, and the latter is a repackaging of Red Hat that is fully binary-compatible. Both are community-supported, which means you can access the servers that host packages for free.

There is a procedure to remove the RHN plugin. Unfortunately you still need a base repo (RHN or Centos) in order to use most the packages in the alternative repos. Since the alternative repos do not have any of the packages that are in the base repos, you run into unresolvable dependency issues. Short version is that you have three basic options, pay to play RHEL, switch to Centos, or switch to something else. While it is true that you could compile everything, at that point you are really not running RHEL anymore.

cant i use centos repos with the RHN configuration remaining as such.

what do i need to do for that?

No, because when yum finds that you are not registered on the RHN, it stops.

and how can i disable rhn repo search by yum........

so that i can only use those repos which i have myself configured.

Besides this, i want to know

What a base repo is?

Can any repo be configured as a base repo or some specific ones?

Also, i have not been abe to use yum much because being new, i messed with yum repos several times and each time ended with not working yum.

Can you please tell me a repository which contains most of the needed programs like firefox, wine, xine, mplayer........

Also, how can i know, which repository is being used by yum when i give a command like

yum install "packagename"

Thank You!

You have to remove the RHN plugin in order to bypass that issue and a couple of other things. You can do a google search on using Centos repos on RHEL and find lots of different instructions. It is usually much easier and more reliable to just switch to Centos.

A base repo is a repo that provides the base packages. For el5 (RHEL5 or Centos5) there are two main base repos, the RHEL5 repo(pay only) or the Centos repo. All the other third party repos will not have the base packages (becuase they are provided by the base repo) but instead provide packages that are not in the base repo.

If you use 'yum info packagename' it will tell you which repos and which versions each repo has. If you use the short name of the package (say just firefox) you will normally install the highest version number it can install.