ABSTRACT
Transmission Control Protocol/Internet Protocol (TCP/IP) consists of several distinct protocols, each of which is used to communicate a different type of message. This chapter examines two packet capture programs: Wireshark and tcpdump. It focuses on netcat, which is often referred to as the Swiss army knife of network communication. Netcat is a text-based program that allows user to read and write directly over network connections by using TCP and User Datagram Protocol (UDP). The chapter then focuses on specific Unix/Linux network programs that relate to obtaining, displaying, and changing IP addresses. It also focuses on some network programs: ping, traceroute, netstat, and focuses on the other functions of ip. ping, traceroute, and netstat are available in Linux/Unix, Mac OS X, and Windows. ip is not available in Windows. The chapter also focuses on the programs that utilize the network rather than those that test the network and focuses on Domain Name System (DNS) lookup programs nslookup, whois, host, and dig.
