Configure a default software repository for your system.

Yum-config-manager --add-repo=http://content.example.com/rhel7.0/x86-64/dvd” is to generate a file vim content.example.com_rhel7.0_x86_64_dvd.repo, Add a line gpgcheck=0

Yumcleanall

Yumrepolist

Almost 4305 packages are right, Wrong Yum Configuration will lead to some following questions cannot be worked out.