Chapter Summary

This chapter discusses some of the aspects of the TCP/IP protocol suite. It looks at some of the most commonly used protocols in the suite, as well as the function of ports and the port assignments for some of the most common protocols. Understanding the functions of the protocols and their associated port assignments is very important when you're working with security products and reconfiguring services.

A network that uses TCP/IP has a number of services that offer needed functionality. Services such as DHCP and NAT offer a solution to the time-consuming and sometimes problematic task of IP addressing. DNS and WINS offer name resolution services that can allow users to access hosts by using easy-to-remember names rather than TCP/IP addressing. Another TCP/IP-based service, SNMP, allows a network to be managed from a central location.

IP addressing is a major topic, and it is very important for network administrators to understand it. Of particular importance are the structure of the addresses and the classes in which they fit. Understanding subnetting allows network administrators to use the allocated IP address space in the most efficient way possible.

An important component of configuring TCP/IP addressing on a system is the default gateway. Without a default gateway address, a system can communicate only with other systems on the same subnet.

This chapter also examines the purpose of private and public networks and their role in a TCP/IP network environment. As the IP address space continues to be depleted, such concepts will become increasingly important.