Linux Shell Scripting Cookbook - Third Edition

Introduction

Networking is the act of connecting computers to allow them to exchange information. The most widely used networking stack is TCP/IP, where each node is assigned a unique IP address for identification. If you are already familiar with networking, you can skip this introduction.

TCP/IP networks work by passing data packets from node to node. Each data packet contains the IP address of its destination and the port number of the application that can process this data.

When a node receives a packet, it checks to see if it is this packet's destination. If so, the node checks the port number and invokes the appropriate application to process the data. If this node is not the destination, it evaluates what it knows about the network ...