ANSWER:

Here is the shortest answer that I can provide while still giving good information:

The domain www.ABC.com points to an IP address 123.123.123.123
Your PC asks a local DNS resolver what the IP is. The DNS resolver tells your PC, and it sends packets that are pointed to that IP (123.123.123.123) Your ISP has a network node. It looks at the IP address and it says “I know where that needs to go!” and it sends it off. If it doesn’t know where to send the packets, it relays them to a different node that does know. When the packets reach the destination, it is up to the local routers at that building to send it to the correct local IP (192.168.x.x).

IP addresses are handed out by a regional authority, which gets its IP addresses from a global authority called IANA (ironically it is funded by the US Defense Dept).

As comments have said, there is a dictionary’s worth of information regarding this.

wolfo9999 from http://superuser.com/questions/597537