ABSTRACT
The TCP/IP protocol suite includes a number of built-in diagnostic tools that developers provide as associated applications running under the operating system that supports the suite. Thus, the primary focus of this chapter is on a core set of applications that can be used to obtain insight into the flow of data across a TCP/IP network. Through the use of the application programs discussed in this chapter, one can determine if the protocol stack is operating correctly on a host, whether or not a host is reachable via a network, and the delay or latency between different networks with respect to the flow of data from one network to another. Because knowledge of the Domain Name System (DNS) is important to obtain an understanding of the operation and constraints associated with different applications that provide a diagnostic testing capability, an overview of DNS is given in the first section of this chapter. Once this is accomplished, the remainder of the chapter focuses on the operation and utilization of applications that provide a diagnostic testing capability.
