recently i installed centos 7 and happy to say back to play with linux. so as first step after installation was the configure network.
first need to check what are the available interfaces in current system. to check that we can use ifconfing -a command
then select the interface you need to active and give following command. mostly with ethernet it will be eth0
ifconfig eth0 up
it will try to make connection with dhcp server and request ip and assign that ip to interface
or else we can assign ip to that interface