Introduction to Linux networking and security
Wei-Mei Shyr, Brian Borowski · XRDS Crossroads The ACM Magazine for Students · 1999
Linux is a member of the UNIX family but is different than most UNIX implementations because it provides a great UNIX server/workstation environment at a low cost, can be run on a wide variety of platforms, and contains no proprietary code.In this article, we will give a brief introduction to the IP networking services, how to configure them, and how to set up a relatively secure Linux workstation.Please note that the examples given here are from the Slackware distribution.The paths of the files might be different on other distributions of Linux. Linux TCP/IP Network ServicesLinux supports a full and high quality implementation of the TCP/IP networking protocols.With a network interface card or a modem and PPP, one can connect a machine to a local area network or the Internet and have access to many additional services and network utilities.Linux provides two methods of establishing host-network services.Servers can either run stand-alone or under the control of a program called inetd.Heavily used services will usually run stand-alone.This means the service does all the management and listening on a socket or port.The most common stand-alone services are inetd, syslogd, portmapper, named, and routed.The file /etc/rc.d/rc.inet2configures the stand-alone services.Here is an example of /etc/rc.d/rc.inet2#!/bin/sh # # rPREc.inet2This shell script boots up the entire INET system.# Constants.NET="/usr/sbin" IN_SERV="lpd"