Being able to ping out to a server and see if its responding is a great way to troubleshoot connectivity issues. But what if you’re not able to ping ANY server? Does that mean that your entire network is down? Does it mean that your network cable needs to be replaced? Does it mean that your network card is going bad? Or could it possibly be that sunspots, magnets, aliens and the Men In Black are all conspiring against you? The answers to these questions could be very difficult, but at the very least you can rule out if your network card is going bad. 127.0.0.1 is the loopback connection on your network interface card (NIC)- pinging this address will see if it is responding. If the ping is successful, then the hardware is good. If it isn’t, then you might have some maintenance in your future. 127.0.0.1 and localhost mean the same thing as far as most functions are concerned, however be careful when using them in situations like web programming as browsers can treat them very differently.