This chapter covers the following subjects:
- The ping and traceroute Commands: This section explains how the ping and traceroute commands work, along with the nuances of how they can be used to better troubleshoot routing problems.
- Troubleshooting the Packet Forwarding Process: This section examines the packet forwarding process, focusing on host routing and how routers route packets. It also covers issues related to forwarding packets in both directions between two hosts.
- Troubleshooting Tools and Tips: This section covers a wide variety of topics that have some effect on the packet forwarding process. It includes many tips about various commands and concepts that can aid the troubleshooting process.
This troubleshooting chapter has several goals. First, it explains several tools and functions not covered in Chapters 4 through 6—specifically, tools that can be very helpful when you're analyzing problems. This chapter also reviews concepts from all three of the other chapters in Part II, "IP Routing." It pulls together the concepts by showing a suggested process for troubleshooting routing problems, as well as examples of how to use the process. The second half of the chapter focuses on a series of troubleshooting tips for many of the specific topics covered in Chapters 4 through 6.
"Do I Know This Already?" Quiz
The troubleshooting chapters of this book pull in concepts from many other chapters, including some chapters in CCENT/CCNA ICND1 Official Exam Certification Guide. They also show you how to approach some of the more challenging questions on the CCNA exams. Therefore, it is useful to read these chapters regardless of your current knowledge level. For these reasons, the troubleshooting chapters do not include a "Do I Know This Already?" quiz. However, if you feel particularly confident about troubleshooting IP routing features covered in this book and CCENT/CCNA ICND1 Official Exam Certification Guide, feel free to move to the "Exam Preparation Tasks" section near the end of this chapter to bypass the majority of the chapter.