A server is a computer or device on a network that manages network resources. Servers are often dedicated and they perform only their server tasks.
D (Network and subnet parts) . When using classful IP addressing concepts as described in Chapter 13, Analyzing Subnet Masks, addresses have three parts: network, subnet, and host. For addresses in a single classful network, the network parts must be identical for the numbers to be in the same network.
Because address allotted to the network ID varies, depending on the address. Most IP addresses fall into the following address classes: Class A addresses: The first 8 bits of the IP address are used for the network ID. The final 24 bits are used for the host ID. Class B addresses: The first 16 bits of the IP address are used for the network ID. The final 16 bits are for the host ID. Class C addresses: The first 24 bits of the IP address are used for the network ID. The final 8 bits are for the host ID. Address Class and Network Type. More bits lead to more combinations.