centos 7.1 - error repository

The problem is config of dhcp, try typing

dhclient

Uncomment baseurl in this file: /etc/yum.repos.d/CentOS-Base.repo

#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/

In this block:

[base]
name=CentOS-$releasever - Base
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

By uncomment, I mean change this: #baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/, to this: baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/ (remove the #).

Check your resolv.conf to see where your name server is pointing. Make sure it's something legit as mine was pointing to an old DNS server on the network that was wiped out. I updated it with the new IP address et voila!