You may have heard the words "class C network" when referring to different types of IP addresses and Internet connections. Generally speaking, each computer that access the Internet has to have an unique IP address. In most cases, when you connect to the Internet from home (for example, using a single computer), your Internet service provider assigns an unique IP address to your computer. But, if you want to connect all the computers in your office to the Internet at the same time using a single Internet connection, you'd usually ask your Internet service provider for a range of IP addresses -- one IP address per each computer. This is where different IP classes come into play -- depending on the number of computers you want to connect, you'd need a different class of IP address range.

Class C

This is the most widely used class by small businesses. When you look at the IP address, you'll notice that class C networks start with a first number that's between 192 and 223 (205.161.74.x for example). There can be up to 2,097,151 class C networks and each network can handle close to 254 computers.

Class B

IP addresses of this type starts with a number between 128 and 191. It's possible to have 16,384 of these networks and each class B network can handle up to 65,534 IP addresses or computers.

Class A

Starts with a number between 1 and 126. Only 126 of these networks are available, however each class A network can handle 16,777,214 IP addresses or computers.