Remember the parts of an IP address for each class.

You need to remember that a Class A IP address is viewed as network.node.node.node, a Class B IP address is shown as network.network.node.node, and a Class C is shown as network.network.network.node. Read the full story

Know the command to enter Ethernet interfaces from the global configuration mode. The command is the interface command, followed by the interface designation. Read the full story

Know the differences in how UDP sequences packets.
You need to remember that UDP does not sequence packets and is connection-oriented. Read the full story

Understand how to find the valid hosts in a subnet
The best way to do this is to use the equation 256 minus the subnet mask. For example, if you have a 240 mask, you would use 256 240. Read the full story