I try not to just re-post slashdot, but this one was impossible to read at the time because the link got slash-dotted (what happens to a tinny server when all the slashdot readers go and hit it). So figured it’d be handy if I put a copy here and explained what’s up.
In order to appreciate this story you have to know a little about how the internet works. Communications over the internet, at it’s base network layer, uses a protocol called TCP/IP, Transfer Control Protocol/Internet Protocol. These IP numbers are the system of unique numbers given to computers on the internet. Names like yahoo.com acutally map back to an IP number, the domain name is only there to make it alot easier to connect to the number. Other protocols like HTTP, FTP, MSN Messenger, IRC (Internet Relay Chat) all operate as a layer on top of this protocol. It is the IP number system that makes the internet so robust.
According to Wikipedia, IP version 4, the current standard, uses 32-bit addresses, limiting it to 4,294,967,296 unique numbers. These numbers are in Dotted Decimal formant, like 184.108.40.206. Since IP numbers are scarce they are assigned by The Internet Assigned Numbers Authority in ranges. For example, Brock University was assigned 139.57.XXX.XXX and Geulph University 131.104.XXX.XXX, people with old-school cable modems have IPs that start with 24.
There are some numbers that have been reserved for special tasks, for example, 192.168.XXX.XXX was reserved for private networks and is now the IP range used by most home routers and wireless routers. One very useful reservation was the use of 127.0.0.1 to refer to your own computer. For example, if you have a Mac and goto System Preference > Sharing and turn on web sharing you can type 127.0.0.1 in your web browser and see your own web server – it will work with the network unplugged. Wikipedia has more on the classes of IP addresses.