Click the Properties button.

Doing the logic thing One of the great things about binary is that it is very efficient at handling spe- cial operations called logical operations. Four basic logical operations exist, though additional operations are derived from the basic four operations. Three of the operations — AND, OR, and XOR — compare two binary digits bits. The fourth NOT works on just a single bit. The following list summarizes the basic logical operations: ⻬ AND: An AND operation compares two binary values. If both values are 1, the result of the AND operation is 1. If one or both of the values are 0, the result is 0. ⻬ OR: An OR operation compares two binary values. If at least one of the values is 1, the result of the OR operation is 1. If both values are 0, the result is 0. ⻬ XOR: An XOR operation compares two binary values. If exactly one of them is 1, the result is 1. If both values are 0 or if both values are 1, the result is 0. ⻬ NOT: The NOT operation doesn’t compare two values. Instead, it simply changes the value of a single binary value. If the original value is 1, NOT returns 0. If the original value is 0, NOT returns 1. Logical operations are applied to binary numbers that have more than one binary digit by applying the operation one bit at a time. The easiest way to do this manually is to line the two binary numbers on top of one another, and then write the result of the operation beneath each binary digit. The follow- ing example shows how you would calculate 10010100 AND 11001101: 10010100 AND 11011101 10010100 As you can see, the result is 10010100. Introducing IP Addresses An IP address is a number that uniquely identifies every host on an IP net- work. IP addresses operate at the Network layer of the TCPIP protocol stack, so they are independent of lower-level Data Link layer MAC addresses, such as Ethernet MAC addresses. IP addresses are 32-bit binary numbers, which means that theoretically, a maxi- mum of something in the neighborhood of 4 billion unique host addresses can 333

Chapter 24: Understanding IP Addresses