Network Address Translation (NAT), described in Chapter 2, can sometimes make verifying the connection between a host and servers on the Internet difficult. Figure 4-19 illustrates. Figure 4-19 Finding Your Public IP Address In Figure 4-19, host A communicates with server D using its local interface address 192.0.2.100. Unknown to A, router B has NAT…
Ookla’s (and similar) tools test your connection to the Internet, giving you throughput and delay. iPerf tests your network—either locally or to a publicly accessible server—and gives you throughput. Mike’s Traceroute (MTR) shows you the delay and jitter across a network Note MTR runs only on Linux-like systems, so if you want to run it…
Figure 10-4 shows the center-right module of the ISR. Figure 10-4 ISR Center-Right Ports This set of ports and the one to the left of them are replaceable, as you might expect, because of the screws on either end of the module. Each router with replaceable modules uses different terminology, such as NIM, 5M slot…
Table 9-3 lists the key topics for this chapter. Table 9-3 Key Topics for Chapter 9 Key Terms You Should Know Key terms in this chapter include: bandwidth throughput goodput delay jitter speed test iPerf Concepts and Actions Review the concepts considered in this chapter using Table 9-4. You can cover the right side of…
Take the quiz (either here or use the PTP software) if you want to use the score to help you decide how much time to spend on this chapter. Appendix A, “Answers to the ‘Do I Know This Already?’ Quizzes,” found at the end of the book, includes both the answers and explanations. You can…
Racks of equipment, wire running all over the place, lights blinking on and off—when you walk into a large room holding lots of networking gear, you might wonder, “What is all this stuff?” You might feel like the person in Figure 10-1. Figure 10-1 Racks of Equipment The good news is there are only a…
A command-line interface ( CLI) is interactive: the user types commands, and the host returns some response, usually text. Network engineers tend to work with CLIs more than GUIs because • CLIs tend to respond more quickly. • CLIs require fewer resources so they can be implemented in a broader range of devices. • Text…
Open the System Preferences app and select the Network icon. Figure 4-8 illustrates the resulting dialog. Figure 4-8 The macOS Network Configuration Dialog For the wired connection, select either the Ethernet port or a port labeled LAN (Local Area Network). Fields of note include • IPv4 Address: The IPv4 address assigned to the interface. •…
Finally, you can find information about network configuration in the System Information application, customarily located under Utilities in Finder. Two sections contain information on wired network interfaces: Ethernet and Network Locations. Figure 4-11 shows the information in the System Information Ethernet section. Figure 4-11 Ethernet Section of System Information The Ethernet section of System Information…
Like most other hosts, Apple Macintosh computers have a command line you can use to examine and configure network parameters. You can typically find an application called Terminal under Applications, Utilities in the Finder app. Once you have launched the terminal, you can display the network configuration using ifconfig, as shown in Figure 4-10. Figure…