One of the first things to do when testing a potentially dodgy network configuration is to ping this address. If you don't get a reply, then something is seriously FUBARd, and I would suggest reinstallation of your OS.
Also, one of a set of addresses that all internet routers will ignore, ie they will ingore all packets going to/from this address.
These are 10.x.x.x, 192.16.x.x, 127.x.x.x, and here's the interesting one: 172.16-31.x.x
A fun thing to do: tell a Windows script kiddie to try hacking some complicated 127 derived address, eg: 127.56.234.191, tell them they can get lots of porn if they do it, they'll be busy all night.