Lesson 4

Troubleshooting TCP/IP Routing

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Lesson 4: Troubleshooting TCP/IP Routing

The Routing and Remote Access service is one of the more complex components in

Windows Server 2003. Because RRAS can perform so many functions, it has a large

number of configurable settings. Even a minor misconfiguration can prevent the

server from routing traffic properly. The TCP/IP implementation in Windows Server

2003 includes a variety of tools that you can use to troubleshoot RRAS and its various

functions.

After this lesson, you will be able to

■ Use TCP/IP tools to isolate a router problem

■ Check an RRAS installation for configuration problems

■ Troubleshoot static and dynamic routing problems

Estimated lesson time: 20 minutes

Isolating Router Problems

In most cases, administrators discover router problems when communications fail

between computers on the network. However, once the troubleshooter suspects that

there might be a routing problem, the next step is to determine which router is mal-

functioning. Some of the TCP/IP tools in the Windows operating system that can help

you in this respect are discussed in the following sections.

Using Ping.exe

PING is the standard TCP/IP tool for testing connectivity; virtually every TCP/IP client

includes a PING implementation. In the Windows operating systems, PING takes the

form of a command line program called Ping.exe. By typing ping followed by an IP

address on the command line, you can test any TCP/IP system’s connectivity with any

other system.

Note

PING functions by transmitting a series of Echo Request messages containing a sam-

ple of random data to the destination you specify, using the Internet Control Message Proto-

col (ICMP). The system that receives the Echo Request messages is required to generate an

Echo Reply message for each request that contains the same data sample and return the

messages to the sender.

Compared to other tools, PING has limited utility when you are trying to locate a mal-

functioning router. You might be able to ping a router’s IP address successfully even