Overview of Linux Networking

Avinash Meetoo

avinash@mauritius-linux.org

Mauritius Linux User Group

http://www.mauritius-linux.org

Small case study : Rina's wishes

Rina has 3 computers at home running Linux

She wants to network them to be able to :

Share files among the computers

Print from any computer to one shared printer

Browse the Internet from any machine using only one modem

What are her hardware and software requirements ?

What is a computer network ?

Physical interconnection of several computers

Main uses:

Share resources

File, printer, modem...

Distributed computing

Have a program running on different computers at once

What is a bus topology ?

Logically :

Main property : everyone receives all

Terminator

Computer

Bidirectional cable

What is a bus topology ?

Physically :

Resistant - Easy to install - Cheap

Computer

Repeater

Why Linux ?

True 32-bits multitasking operating system

Networking is tightly integrated with the OS

Very robust under heavy loads

Numerous applications are available

Both client applications and services

Everything is Free !

What is a protocol ?

Common language between computers on a network

International standards

TCP / IP (Internet)

IPX / SPX (Novell)

NetBEUI (Microsoft)

...

TCP / IP

Developed by the U.S. DoD in the 1960's

IP

Addressing

Routing

TCP

Virtual connection

Segmentation & reassembling

M1

M2

M3

192.168.1.1

192.168.1.2

192.168.1.3

To: M3

Some common services

DNS = Domain Name Server

Manages mapping between host name and IP address

M1 => 192.168.1.1, M2 => 192.168.1.2, etc.

Message sent to M3 instead of 192.168.1.3

Linux specific

Provided by : BIND (Berkeley Internet Name Domain)

More info in : DNS-HOWTO

Some common services...

SMB = Server Message Block

Share files and printers among Linux and Windows machines.

Print from Linux to a printer connected to a Windows PC

Share a directory containing files between two Linux boxes

IMPORTANT

Linux and Windows boxes can work together

Linux specific

Provided by : Samba

More info in : SMB-HOWTO, Samba Manual

Some common services...

HTTP = Hypertext Transfer Protocol

World Wide Web service

Web pages containing text, images, sounds

Server-side programming using PHP, CGI-BIN

Linux specific

Provided by : Apache

the most popular Web server on the Internet

85% of all servers according to Netcraft

More info in : WWW-HOWTO, Apache & PHP manuals

Some common services...

SMTP = Simple Mail Transfer Protocol

Handles local mailboxes as well as mails to and from the Internet

Each User of a home network can have his or her own mail address and mailbox => privacy

Linux specific

Provided by : Sendmail, a Mail Transport Agent

“All Internet mails go through Sendmail”

More info in : Mail-Administrator-HOWTO, Sendmail manual, Sendmail-cf documentation

Small case study : Rina's wishes

Rina has 3 computers at home running Linux

She wants to network them to be able to :

Share files among the computers

Print from any computer to one shared printer

Browse the Internet from any machine using only one modem

What are her hardware and software requirements ?

One possible hardware configuration

Homer

Bart

Lisa

Repeater

192.168.1.1

192.168.1.2

192.168.1.3

Modem

Printer

Internet

Shared directories

Responsibilities

Homer

Gateway to the Internet

Will eventually act as a Firewall...

Bart

Handles all shared directories

Lisa

Handles the shared printer

Software required

All machines require Linux (of course :-)

OS + applications like Netscape, StarOffice...

Homer

Driver for modem and network card

Samba client for accessing files and printing

Masquerading capabilities

Provided by : ipchains

More info in : IP-Masquerade-HOWTO, Firewall-HOWTO

Software required

Bart

Samba server providing file sharing

Samba client for printing

Lisa

Samba server for the shared printer

Samba client for accessing shared files

Conclusion

Linux is like good wine

It takes time to learn and appreciate all its finesse...

2001-02-04T12:17:52