Chapter 13. People Like Names, but Computers Like NumbersWhat You Will Learn After reading this chapter, you should be able to
I was driving in the car with my wife the other day, and I needed to call my good friend, Gary. I didn't tell my wife "Hey, I need to call 555-555-1234," but I said something like, "I need to call Gary." (Nope, that's not Gary's real phone number. He might get a few extra calls if I had put his real number in here.) When I actually called Gary, I didn't punch his name into a keypad; rather, I typed in the number. I want to talk to Gary, but the phone company just cares about the phone number I want to connect to. Similarly, users typically refer to names, but computers use numbersspecifically IP addressesto deliver data across the network. Routers route packets based on the destination IP address; there's not a place in the IP header for the name of the destination host computer. So, before a user can succeed at connecting to a server using a name, his computer has to figure out which IP address to plug into the IP packet header as the destination IP address. This chapter covers the basics of how a PC performs name resolution. Name resolution refers to the process of a computer taking a name, typically supplied by the user of the computer, and figuring out the corresponding IP address. |