Troubleshooting Tcp/Ip

Troubleshooting TCP/IP

The sections in this chapter describe common features of TCP/IP and provide solutions to some of the

most common TCP/IP problems. The following items will be covered:

• TCP/IP Introduction

• Tools for Troubleshooting IP Problems

• General IP Troubleshooting Theory and Suggestions

• Troubleshooting Basic IP Connectivity

• Troubleshooting Physical Connectivity Problems

• Troubleshooting Layer 3 Problems

In the mid-1970s, the Defense Advanced Research Projects Agency (DARPA) became interested in

establishing a packet-switched network to provide communications between research institutions in the

United States. DARPA and other government organizations understood the potential of packet-switched

technology and were just beginning to face the problem that virtually all companies with networks now

have—communication between dissimilar computer systems.

With the goal of heterogeneous connectivity in mind, DARPA funded research by Stanford University

and Bolt, Beranek, and Newman (BBN) to create a series of communication protocols. The result of this

development effort, completed in the late 1970s, was the Internet Protocol suite, of which the

Transmission Control Protocol (TCP) and the Internet Protocol (IP) are the two best-known protocols.

The most widespread implementation of TCP/IP is IPv4 (or IP version 4). In 1995, a new standard, RFC

1883—which addressed some of the problems with IPv4, including address space limitations—was

proposed. This new version is called IPv6. Although a lot of work has gone into developing IPv6, no

wide-scale deployment has occurred; because of this, IPv6 has been excluded from this text.

• Troubleshooting Hot Standby Router Protocol (HSRP)