it's hard to say, but try to open the
[code]
http://mirrorlist.centos.org/?releas...x86_64&repo=os where the list of repos is located,
it should open
Code:
http://mirror.lihnidos.org/CentOS/6.3/os/x86_64/
http://mirrors.paknet.org/CentOS/6.3/os/x86_64/
http://ftp.arnes.si/pub/mirrors/centos.org/6.3/os/x86_64/
http://mirrors.prometeus.net/centos/6.3/os/x86_64/
http://centos.fastbull.org/centos/6.3/os/x86_64/
http://mi.mirror.garr.it/mirrors/CentOS/6.3/os/x86_64/
http://mirror.crazynetwork.it/centos/6.3/os/x86_64/
http://gd.tuwien.ac.at/opsys/linux/centos/6.3/os/x86_64/
http://centos.mirroraustria.at/6.3/os/x86_64/
http://centos.digitalnova.at/6.3/os/x86_64/
http://mirror.centos.com.ba/6.3/os/x86_64/
http://ftp.freepark.org/pub/linux/distributions/centos/6.3/os/x86_64/
if not, you have a network problem (not connected to internet ?) not yum problem.