Chapter 22

Troubleshooting Connectivity and Performance Problems

In This Chapter

Protocols in this chapter: ICMP, IP, DNS, SNMP, MIB

Pinging every which way

Finding DNS name server info with nslookup

Stepping through a troubleshooting process

Tracing the route of a packet from start to end

Monitoring your network with a Network Management System (NMS)

Ping — pang — pung. Today we ping, yesterday we pang, and many times we have pung. In this chapter, we describe tools for basic connectivity troubleshooting and walk you through a troubleshooting exercise step by step. Depending on which operating system you run, you may be able to use additional tools for these information-gathering tasks. Most operating systems include their own tools, such as event loggers and graphical monitors, that track processes and display dozens of network utilization statistics. Other vendors sell tools with fancy extensions and user interfaces. You can also find freeware or shareware troubleshooting tools on the Internet. Ultimately, we find that the basic tools in this chapter provide almost all the troubleshooting capabilities you need.

When you start diagnosing network problems, the basic tools provided on all major operating systems are the practical places to start. This chapter describes how to keep it simple — at least at first — with a simple set of tools that work on all operating systems:

ping, ping6 for IPv6 networks on Linux, Unix, and Mac OS X, and ping -6 for ipv6 networks on Windows operating ...

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