please post the FULL output of this
yum repolist all
I don't know about the router or proxy I got the server from datashack.net
HOW is it you do not know if there is a router between YOU and the web ( yes / no)
or if you ARE or ARE NOT using a proxy ( yes / no )
the std network tools for rhel6 are "ifup" "ifdown" "ifconfig"
and please ANSWER the question " How did you install Gnome??? "
yum is VERY dependent on python and Gnome is ALSO dependent on python that IS IN the "BASE" repo
please post the full command you gave to install gnome desktop
it is only one line of text