[CentOS] can NOT update CENTOS use YUM

Sun Aug 9 21:36:20 UTC 2009
John R Pierce <pierce at hogranch.com>

mcclnx mcc wrote:
> Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=5&arch=i386&repo=os
>   
>> error was
>>     
>>> [Errno 4] IOError: <urlopen error (111, 'Connection refused')>
>>>       
>>> Error: Cannot find a valid baseurl for repo: base
>>>       

that error seems to indicate you can't read that URL.

at a shell prompt, try...

$ wget -O - --progress=dot 
"http://mirrorlist.centos.org/?release=5&arch=i386&repo=os"
--14:35:00--  http://mirrorlist.centos.org/?release=5&arch=i386&repo=os
Resolving mirrorlist.centos.org... 204.15.73.243, 72.232.223.58
Connecting to mirrorlist.centos.org|204.15.73.243|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [text/plain]
Saving to: `STDOUT'
http://pubmirrors.reflected.net/centos/5.3/os/i386/
http://updates.interworx.info/centos/5.3/os/i386/
http://mirrors.cat.pdx.edu/centos/5.3/os/i386/
http://mirror.cs.vt.edu/pub/CentOS/5.3/os/i386/
http://mirrors.kernel.org/centos/5.3/os/i386/
http://mirrors.cmich.edu/centos/5.3/os/i386/
http://mirror.clarkson.edu/centos/5.3/os/i386/
http://mirror.nuvio.com/pub/centos/5.3/os/i386/
http://mirror.newnanutilities.org/pub/centos/5.3/os/i386/
http://mirror.linux.duke.edu/pub/centos/5.3/os/i386/

     0K                                                        21.8M=0s

14:35:00 (21.8 MB/s) - `-' saved [494]

as you are in .tw, likely you'd get a different set of URLs back.

if you get errors, debug that.