Try

cat /etc/redhat-release

to get the exact version, inc point version.
Post # 12 is very good advice; stick to Official CENTOS repos only until you get sorted out.

Dear Friends,

Thank you very much for the reply to the previous question.

Here I am facing new problem with yum. When I am executing the command:

#yum -y update.

I am getting following error:

Loaded plugins: fastestmirror, priorities
Loading mirror speeds from cached hostfile
Could not retrieve mirrorlist http://mirrors.fedoraproject.org/mir...el-5&arch=i386 error was
[Errno 4] IOError: <urlopen error (-3, 'Temporary failure in name resolution')>
Error: Cannot find a valid baseurl for repo: epel

Can anyone help me to solve this.

Thanks in advance.

Regards,
Anagha

1. do you really need a pkg that you can only get from the EPEL repo?
2. If so, it could well be what it says 'Temporary failure in name resolution'; try again.
Also, can you get to there via a web browser?

Hmm, so how was I able to upgrade my home server from 5.2 to 5.3 then?

I agree, it might be different to go from 5 all the way to 5.3 but I could certainly upgrade from 5.2 to 5.3 using a yum upgrade as you say you cannot.

same as lee ball, I upgraded via yum update (note: I used update) and it updated all from 5.2 to 5.3.

I was not saying you could not do it. I was saying that it does not matter (on Centos) if you use update or upgrade. A fully updated 5.0 install is a 5.3 install.

I might be joining this post late but I recently had this issue with yum.

First restore the /etc/yum.repos.d/CentOS-Base.repo to where it is fetching from the mirrorlist.
Then back up /var/lib/rpm/__db* files in any directory then follow the following sequences of steps and let us know the results.

ls -l /var/lib/rpm
rm -f /var/lib/rpm/__db*
rpm -vv --rebuilddb
yum
yum clean all # This may be the farest that you have to go.
rm /var/run/yum.pid
yum clean all
yum update

If this fails just restore the __db* back to the /var/lib/rpm directory.