If this is Red Hat Enterprise Linux 7, it's normal that there is no ifconfig. Run
ip address instead.
As to the failing ping: Your error indicates only that name resolution doesn't work. You may actually have internet access. A few simple checks:
can you ping 8.8.8.8?
can you ping an ip address in your local network?
is you basic network configuration correct (ip address, ip route commands)?
Is the system physically connected?
Use a network troubleshooting guide such as
http://www.linuxhomenetworking.com/w...roubleshooting. There are too many possible problems to cover in a forum thread.
