Linux Certification Lab

INTRODUCTION TO LINUX

LINUX is an open source / free software. With its advanced server configuration, Red Hat is putting

Linux as an operating system at the core of enterprise computing. Today Linux is found in Web

infrastructure, file server, ERP, and point of sale system, increasingly in the systems running critical

applications at large companies. Analysts predict that by the end of this decade Linux will be a

common element in the enterprise computing landscape.

“Over the last year, we’ve seen Linux go from being focused on small and medium business to

being used very deep in the enterprise”, says Paul Cormier, executive vice president of engineering

at Red Hat, a leading Linux platform provider.

Salient Features of LINUX

Linux is the fastest operating system in the world. It runs much faster than Windows 9X/NT. It is

about 1.2 to 3 times faster than Windows 9X/NT. In command-line console mode without X-

window it runs even faster (console mode is ideal for Database servers, Apache Web servers,

Email servers, News servers, File servers, DNS servers, Print servers,  Network Computer servers,

etc..). Linux is also the most powerful yet most simple and easy to use operating system in the

world.

Linux is the most reliable OS. Windows 9X/NT fails the CRASH_OS_TEST Programs and only

Linux passes. Also commercial UNIX’s like IRIX, Solaris,HPUX, AIX, SCO all fail the crash test

and Linux is the only OS which passes the crashme test. Very often Windows 95 users will get

GPF errors and the system freezes. Linux is very robust because it is built by millions of people on

internet and there are no errors in the kernel. It runs for one full year without any re-boots or any

problems non-stop, guaranteed. It is the best designed OS.

 

Linux has an excellent scalability - it runs on Uni-processor, Multi-processors, Parallel Processors

and even Super-computers. It fully supports SMP (Symmetric Multi-Processing) boxes with more

than one CPU. Windows 95 supports only one CPU box. Linux scales much better than NT on

SMP.

 

Linux is fully 32-bit & 64-bit operating system. And it is very modular and is already ported to 64-

bit chips like DEC alpha, Sun Microsystems UltraSparc, Intel IA64, Motorola PowerPC,

Transmeta Corp Crusoe chip and GNU/GPL Freedom 64-bit CPU. Whereas Windows 95 has a

major chunks of 16-bit code in its kernel and MS Windows runs only on one type of chip - "Intel

chip".

 

Linux is a very secure OS. Windows 95 is not a secure OS, break-ins are easy. Windows 95/2000,

NT, MSDOS have computer viruses. But Linux does not have any viruses. Computer viruses cause

lot of damages to Windows 95/2000/NT but not to Linux.

Linux is very mature and is one of the oldest operating system in the world. UNIX (which is

another name for Linux) was born in AT&T Bell Labs 27 years ago for Telecom research. Linux

(UNIX) is the end-result of 27 years of research and development effort by U.S/European

Universities and mega-corporations of Europe / America. It took 27 years to create vast amount of

UNIX information, and all that info is now just sitting inside this Linux cdrom on our hand. For

example programs like 'grep' had not changed for the past 27 years and they are still used in Linux.

Functionality and command line options of grep had not changed for the past 27 years. Linux

started the Linux during 1991, but he borrowed lot of concepts, code from UNIX and this means

Linux is 27 years old. Today Linux is the OCEAN wherein all other unixes like Solaris, HPUX,

and AIX merge into. And in near future all other unixes will be replaced by Linux.

 

Linux is less demanding on system resources. Linux runs on 386 PC with as little as 2 MB RAM in

command-line console mode. Windows 95/NT cannot because the graphic engine is included in the

kernel, which makes Windows 95/NT a resource hog. Graphic engine makes the Windows 95/NT

extremely unreliable and unpredictable. Linux can do everything that Windows 95/NT does but

Windows 95/NT cannot do everything which Linux does. In Windows 95/NT there is no option for

the user to run in command-line console mode without any graphics. Unlike Windows95, X-

window can run with very minimum resources, it runs on 486 boxes with just 8MB of RAM.

 

Linux uses X-window which is an advanced network-windowing system, whereas Windows 95/NT

is a standalone single-workstation windowing system. For example, using X-window, users can

display output on any workstation-monitor attached anywhere in the network. There is a command

called "xhost" in Linux and display environment variable, export display=`hostname`:0.0. Like this

there are lots of functionalities in X-window which are missing in Windows NT/95. X-Window is

an industry standard which was developed in MIT and is a very powerful network windowing

system. With X-window you can run programs on super-computers and display on your Linux

desktop locally. Even though X-window is network-resource intensive, it is becoming increasingly

popular because of the availability of very low cost, high speed networking like 1 Gig bit Ethernet

cards, 100 Megabit Ethernet cards, DSL lines, Cable-Modems, Frame-relay and ATM networks.

Linux has very low total_cost_of_ownership since Linux supports diskless nodes. Cost of

maintaining Linux is five times lower than MS Windows.

Linux supports remote system administration whereas Windows NT/95 does not. We can remote

login and do many system administration tasks, for example like adding users, reboot a Linux

server from a remote terminal hundreds of miles.

 

Linux runs most windows applications (16bit) like MSOffice, MSWord using WABI ($40), WINE

(free) and MSDOS applications using DOSemu, FreeDOS, and Dr.DOS. But Windows95/NT will

run only few of UNIX and Linux applications.

 

Linux supports su (super user) command. Using su command it is possible to switch user without

logging off. For example 'su - root' will login as user 'root'. In Windows NT/95 you must log off

completely to switch user. Linux has remote commands like 'rlogin', telnet, etc. While Windows

NT/95 does not have.

 

Linux kernel is very small and it can fit on a single floppy. It is less complex but very sophisticated

and powerful. Small kernel means it is very reliable. Linux applications are much bigger running

on top of the Linux Kernel.

 

Linux has many powerful desktops like KDE desktop, GNOME, Triteal CDE, Motif mwm, Open

look olwm, twm, fvwm95, xdm, xsm, Windows Afterstep, Window maker (NeXTstep-lookalike),

Qvwm, amiwm (amiga), mlvwm (mac) etc. KDE desktop is much more user friendly than

Windows95! You have more freedom and choice in Linux desktops as compared to Windows

9X/NT.

 

Linux OS needs only 200 MB of disk space for installation. Linux supports dual boot on the PCs -

that is, you can have Windows95/NT on one partition and Linux on other. During system startup

user can select to load Linux or Windows 95 and vice versa. Nowadays PCs are shipped with 6

Gigs of disk space.

 

Linux runs on many hardware platforms - Intel, Motorola, PowerPC, RISC, DEC Alpha, MIPS,

ARM, Transmeta Crusoe, Sparc architectures and GNU Freedom-64-bit CPU. Linux is already

ported to 1024 CPUs super computer (Fujistu, Hitachi, Sun, Intel & others). Intel corporation had

built the world's fastest super-computer with 10240 Intel Pentium CPU’s (more than ten thousand

CPU’s) which is based on a system similar to Linux.

 

Linux is 100% POSIX compliant OS, whereas Windows NT/9X are not. POSIX is IEEE (Institute

of Electrical Engg) standard as well as ANSI and international ISO standard spec. U.S. govt

generally require full compliance of POSIX on any operating system. Most of the Unix's like

Solaris, HPUX, AIX, SCO are 100% POSIX

 

We can get the complete source code for Linux OS and all of its applications, whereas Windows

9X/NT is proprietary and we get only the binaries. Having the source code of Linux is vital for

companies because they can quickly add advanced features and share it with every other company

in the world.

 

Linux is free of any cost. Downsides of Windows 9X/ NT is that we need to pay $200 (US dollars)

per seat for Windows 95 and $800 (US dollars) per seat for Windows NT. And Microsoft

applications like MS Office, C++ compilers and others will cost further $400,000 US dollars. It is

better to spend money on hardware and use Linux as the software.

Linux is trouble free and we will not have any problems with Linux, whereas you will have more

headaches with Windows 95/NT (MS is not as reliable as Linux).

 

Linux more than 1900 software packages on cdrom and many more are being developed world-

wide. All the software packages are in a single Linux cdrom.

 

Linux was awarded “The best Network Operating system 1997/98/99/2000”, by many computer

magazines’ (US InfoWorld, European publications).

 

The movie Titanic was created using Linux on Digital Alpha. Linux was used to create computer

graphics, animations of all the shots in the movie Titanic.

 

Linux was also used for storing data from experiments in the space shuttle. Linux was orbiting the

earth in space.

Advantages of Linux:- Virus proof Advanced OS Crash proof

Economical Secured User friendly GUI

Multi-user Multi-tasking Multi-desktop

Powerful networking Variety of servers

Who are using Linux:- Private sector Government sector

Raymond’s Air-India

ICICI Central Excise

IDBI Govt. of MP

Bombay Dyeing Govt. of Goa

Asian Paints Govt. of Kerala

Bharat petroleum Govt. of A P etc.

Reliance Railways

LINUX INSTALLATION

Before Linux installation, you must really know about what is hard drive partition. For Linux

installation we need to insert the installation cd of Red Hat Linux to CDROM and boot. Most of the

installers give you an option between text and graphical install; you need to select “text” if your

computer memory is restricted.

Linux software comes in packages. No matter what distribution or version of Linux you have, the

CD contains packages that make the base operating system a rich selection of networking “clients”

and “servers” with appropriate configuration and monitoring tools, some end-user text mode

application, base X-window system and at least one GUI desktop.

The installation program will ask you several things to do like type of boot loader configuration. It is

better to select GRUB boot loader configuration. After this you will be asked to select the type of

doing partitions. It is recommended to choose disk druid type. In this you will be asked to do

partitions on available free space. In Linux there is all file system concept unlike windows. The

minimum required file system for installation of Linux are /, /boot, swap and /usr. After doing these

partitions the procedure will ask which packages to install. If you select “workstation” the packages

normally found on servers are omitted from your installation. If you select server installation then the

end-user applications will not be installed. You can also chose to install “everything”, best option for

installation on personal computers at your home for new users. For expertise users there is an option

of selecting individual packages as per your requirement. Now installation of Linux all in the form of

packages starts and takes time according to the packages selected. After completion the system

reboots and Linux will start successfully. Types of installation Method CD-ROM NFS FTP HTTP HARD DISK Through kickstart method

Types of Bootloader GRUB LILO

Hard Disk Partitioning Method Disk druid fdisk

Type of X-Window System (Desktop) GNOME – GNU Network Object Model Environment KDE- K Desktop Environment

LINUX KERNEL & SHELL

KERNEL The core of the Linux system is the kernel-the operating system program. The kernel controls the resources of the computer, allotting them to different users and tasks. It interacts directly with the hardware, thus making the programs easy to write and portable across different platform of hardware. Since the kernel communicates directly with the hardware, the parts of the kernel must be customized to the hardware features of each system. However, the kernel does not deal directly with a user. Instead, the login process starts up a separate, interactive program, called the shell, for each user.

SHELL

Linux has a simple user interface called the shell that has the power to provide the services that a user wants. It protects the user from having to know the intricate hardware details.

Feature of Shell:

Command Execution Redirection Background processing History Aliases

Variables File Name Expansion Command completion

Types of Shell in Linux:

Bash- “Bourne Again Shell” Pdksh-“Public Domain Korn Shell” Tcsh- “Tom’s C Shell” Ash- “A Shell” Zsh- “ Z Shell”

Linux Utilities and Application Program

The Linux utilities or commands are a collection of programs that service day-to-day

processing requirements. These programs are invoked through the shell, which is itself another utility

LINUX FILE SYSTEMS

MS-DOS, VFAT, and UMSDOS:-These filesystems allow you to read MS-DOS-formatted filesystems. MS-DOS lets you read pre–Windows 95 partitions, or regular Windows partitions within the limits of short filenames. VFAT lets you read Windows 95 and later partitions that are formatted to this filesystem. UMSDOS allows you to run Linux from a DOS partition (not currently supported by Red Hat).

ISO 9660 CDROM: - The standard filesystem for CD-ROMs. It is also known as the High Sierra File System or HSFS on other UNIX systems.

Minix:-The standard filesystem for the Minix operating system. This is the original default Linux filesystem. The current Linux standard is ext3.

NTFS:- NTFS is the Microsoft Windows NT/2000/XP filesystem designed for username / password security. Currently supported as a read-only system.

OS/2 HPFS: - The standard for IBM’s OS/2 operating system.

/proc: - The /proc filesystem is a Linux virtual filesystem. Virtual means that it doesn’t occupy real disk space. Instead, files are created as needed. /proc is used to provide information on kernel configuration and device status.

/dev/pts: - The /dev/pts filesystem is the Linux implementation of the Open Group’s Unix98 PTY support.

ROM:-The ROM filesystem is a read-only filesystem, intended primarily for initial RAM disks such as an installation boot floppy.

Second Extended (ext2):-The basis for ext3, the standard Linux filesystem. The ext3 filesystem is essentially ext2 with journaling.

Third Extended (ext3):- The standard Linux filesystem.

NFS:-The Network File System. This is the system most commonly used to share files and printers between Linux and UNIX computers.

SMB: - Server Message Block (SMB) is based on Microsoft and IBM network protocols. Linux can use SMB to share files and printers with Microsoft Windows operating systems.

NCP: - Netware Core Protocol (NCP) is the network filesystem used by Novell, using the IPX/SPX protocol stack. NCP allows Linux to use NCP as a client Types.

Filesystem

In all of the preceding configurations, automatic partitioning sets up multiple volumes—separate volumes on each directory. The advantage of separate partitions for certain directories is that it limits the risks to your system. For example, many Webmasters configure their Web sites to write daily log files with data relating to all users who visit their sites. These files can become quite large, especially for large online merchants. Before you decide how to set up partitions, you need to know about each of the major Linux directories. Linux directories are organized according to something known as the Filesystem Hierarchy Standard (FHS). Filesystem Hierarchy Standard

The FHS is a standard for organizing directories for Linux- and Unix-based systems. Every FHS-compliant operating system starts with a top directory, root, symbolized by the forward slash. All other directories are subdirectories of root.Directory Description

/ The root directory. Other directories are below root in the FHS hierarchy. Unless mounted separately, the contents of other directories are in the root directory partition.

/bin Essential command line commands. Do not mount this directory on a separate volume, or else you may not be able to find these commands when you use a rescue disk.

/boot Linux startup programs. Normally includes the Linux kernel. Separate/boot partitions are common; the default size is currently 100MB.

/dev Linux device drivers. Do not mount this directory on a separate partition. /etc Basic configuration files.

/home User home directories (except the root user).

/lib Program libraries. Do not mount this directory on a separate partition.

/mnt Mount point for removable media (floppy disks, CD drives).

/opt For applications, such as StarOffice or VMWare.

/proc Running kernel processes.

/root Home directory for the root user. Do not mount this directory separately.

/sbin System administration commands. Do not mount this directory separately.

/tmp Temporary file default directory.

/usr Small programs.

/var Log files, print spools, and other variable-sized data.

/etc All configurations files.

X WINDOW SYSTEM

Provides foundation for the graphical component of Linux. Created in 1986. Client / Server Architecture. XFree86 – Free Open Source implementation of X. Flexibility of the core components

Use fonts on local or remote machine. Different graphical login-gdm,kdm,xdm

KDE – KDE is the k Desktop Environment. It consistent desktop environment. It uses Qt widget set.

GNOME – Consistent easy to use desktop environment. GNOME has collection of tools and libraries to develop software. It uses GTK+ widget set.

Web Browsers Mozilla- Standard web browser. Lynx – Original text mode browser. Links – Advanced text mode browser. Konqueror – KDE file manager/web browser.

Mail Clients Mozilla mail Kmail - KDE mail client

Office Application – KOffice- Integrated office suite for KDE. Open office – open source version of staroffice.

GUI Editors – Xemacs – X version of emacs editor. Kwrite – Default KDE text editor.

Redhat-config-xfree86 Red hat developed X configuration tool Monitor selection Resolution selection Video card selection

Xchat – Full-featured IRC client gftp – Graphical ftp client. gimp – The GNU image Manipulation Program. Window Manager – Special X client. Perform window movement, resizing, focus.

LINUX NETWORKING

For networking firstly your hardware must be properly configured. Your network card should have

been setup during the Linux installation or after the installation. Under Linux most drivers for

network cards are implemented as modules, after the module is inserted, you may want to inspect the

file /proc /modules to see if the module is loaded. The module configuration file is modules.conf

in /etc. After setting up the network and connecting the cables, set up the network by running the

command: - netconfig

While setting up the network, doesn’t mess up with the “loop back driver” which has the IP address

127.0.0.1. It is always there-it is the IP through which the computer talks to itself. IP address is

allocated either statically or dynamically.

For Linux Networking (communication through a network), the two basic Requirements are Media

and Rules:-

1. By media we mean the communication link (cables), hubs and switches. It may be wired or

wireless. Hubs are dumb, not an intelligent device. It works at the Physical layer whereas

Switches are intelligent devices and works at Data link layer. To obtain good performance we

make use of Switches. In a Switch, direct routing is possible, the data packet is unicasted and not

broadcasted, the packet doesn’t traverse to all the port but direct connection is made via IP

address. Thus it has high performance; Switches maintain the IP address table for mapping

process.

2. By rules we mean the set of protocols used for communication. Rules or the Protocol to be used

depends on the OS on the end systems, if both the end- Systems have MS-Windows then for

small network we use Netbui protocol & for larger networks use of TCP/IP is made. End systems

having LINUX as OS Make use of TCP/IP protocol.

Some Basic Networking Command1) Ping – Measures connectivity and network latency between local & remote system. It uses ICMP echo packets.

Example: ping 192.168.0.1 Or ping www.redhat.com

2) traceroute – Shows network path between local and remote systems. Useful for pinpointing network congestion. Example: traceroute www.redhat.com 3) netstat – Lists network statistics and parameters, including Network Connection, Routing table, Interface statistics.

Example: netstat –rn Or netstat –a

4) ifup/ifdown - For each installed network adapter, there is a Corresponding ifcfg-* file in/etc/sysconfig/network Scripts. You can activate or deactivate that adapter with the ifup and ifdown commands. Either one of the following commands will activate the eth0 network adapter:

Example: ifup ifcfg-eth0 ifup eth0

5) ifconfig - The ifconfig command is used to configure and display network devices. Here is some sample output of an ifconfig command:

# /sbin/ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:50:56:40:1E:6A inet addr:192.168.199.131 Bcast:192.168.199.255 Mask:255.255.255.0 UP BROADCAST NOTRAILERS RUNNING MULTICAST MTU:1500 Metric:1 RX packets:11253 errors:0 dropped:0 overruns:0 frame:0 TX packets:1304 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:100 RX bytes:2092656 (1.9 Mb) TX bytes:161329 (157.5 Kb) Interrupt:10 Base address:0x10a0

# /sbin/ifconfig eth0 207.174.142.142The first parameter, eth0, tells us which interface is being configured. The next argument, 207.174.142.142, indicates the new IP address being assigned to this interface. If we want to make sure our change worked, we issue the ifconfig command again to view its current settings.

# /sbin/ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:50:56:40:1E:6A inet addr: 207.174.142.142 Bcast:192.168.199.255 Mask:255.255.255.0 UP BROADCAST NOTRAILERS RUNNING MULTICAST MTU:1500 Metric:1 RX packets:11253 errors:0 dropped:0 overruns:0 frame:0 TX packets:1304 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:100 RX bytes:2092656 (1.9 Mb) TX bytes:161329 (157.5 Kb) Interrupt:10 Base address:0x10a0

DNS SERVER DNS is the Domain Name System, which maintains a database that can help your computer translate domain names such as www.redhat.com to IP addresses such as 216.148.218.197. As individual DNS servers are not large enough to keep a database for the entire Internet, they can refer requests to other DNS servers. This section addresses two basic DNS server configurations: a caching-only server, and a primary DNS server for a domain. The key configuration files to support such servers include /etc/nsswitch.conf, /etc/resolv.conf, and /etc/hosts,/etc/named.conf,/var/named/.

Types of DNS server

1) Master DNS Server - contains the master copy of data for a zone.2) Slave DNS Server – provides an automatic backup to the master name server.3) Caching-only Server - When a request is make for a Web page such aswww.osborne.com, network asks the configured DNS server for the associated IP address. This is usually known as a name

query. If the DNS server is outside your network, this request can take time. If you have a caching-only name server, these queries are stored locally, which can save significant time while you or others on your network are browsing the same sites on the Internet.

Service Profile: DNS

Type: System V-launched daemon Packages: bind,bind-utils Daemons: named Script: named Ports: 53 udp, 53 tcp Configs: /etc/named.conf,/var/named/* Related: redhat-config-bind

Domain Name System

DNS root

com net us jp Top-level domain

example.net second-level domain

www.example.net omoini.ny.us

fox.trot.example.net www.omoini.ny.us

The DNS root has a small set of top-level domains that rarely changes. Some of them are as aero, com, net, edu, gov, info, org, int, and name. In a domain name like www.example.net, net is a first-level name within the root, example is a second-level name within net, and www is a third-level name within example. The example.net domain contains another third-level domain called fox.trot. The tree can extend to any number of levels, but in generally it is not more then four levels deep.

DHCP SERVERDHCP provides methods for hosts on a TCP/IP network to request and be granted IP addresses, and also to discover information about their local network. One machine on an Ethernet segment is designated the dhcp server and configured to answer these requests.IP addresses are either dynamically assigned from a range or pool of address, or statically assigned by MAC address.

Service Profile: DHCP Type: System V-launched scripts Packages: dhcp

Daemons: dhcpd Scripts: dhcpd Ports: 67(bootps),68(bootps) Configuration: /etc/dhcpd.conf Related: dhclient

Example: Dhcp server provides ip address between 192.168.0.1/192.168.0.20

192.168.0.1

DHCP SERVER

SWITCH

PC 1 PC 2 PC 3192.168.0.18 192.168.0.19 192.168.0.20

DHCP SERVER PROVIDE IP ADDRESS DYNAMICALLY

LINUX AS ROUTER

For a Linux machine to be called a router it has to either have at least two network cards or it should have IP aliases set up.

The steps are as follows: Configure the network cards Run the netconf command Select the Routing & Gateway option Provide the required IP address Select Enable Routing option. Accept the configuration Restart the network service

CLASS A 10.0.0.2 10.0.0.3NETWORK

Switch 1 eth0 10.0.0.1

eth1 192.168.0.1 Switch 2

CLASS C NETWORK

192.168.0.2 192.168.0.3

Fig: LINUX AS ROUTER

LINUX AS FIREWALL A Firewall is quite simply a TCP/IP host on the internet, with multiple IP interfaces or network cards. One interface is connected to the internet, and other is connected to the internal network.

Firewalls are intended to keep the flames of internet hell out of your private LAN, or, to keep the members of your LAN pure and chaste, by denying those accesses to all the evil internet temptations.

Types of Firewall

1) Packet filter:- Screening Router Filters Ip packets Route between networks Protocol independent Only filters packet header Minimal hardware needs Work on transport layer

2) Dual-homed host:- proxy

Filters protocols No routing between networks Not all protocols supported Can filter content High hardware requirements Work on application layer

Iptables & netfilter

Netfilter is Linux 2.4’s network filter stack. The filtering stack was redesigned to have packet filtering, mangling and network address translation in one implementation. Iptables is netfilter’s filtering module. Iptables now uses different tables for different action. Generally filter and nat tables are used. There are five built-in chains (INPUT, OUTPUT,FORWARD, PREROUTING AND POSTROUTING).The chains represent special hooks in the netfilter code that are used for the packet filtering.

Iptables syntax and commands

Iptables [-t table] <action> [pattern] [-j target]

Here action determines the action to perform on the table. Here pattern specifies when the rule matches. Target defines what happens to the packet.

Iptables –t filter –A INPUT –s 192.168.0.254 –j DROP This deny the any packet arriving from IP address 192.168.0.254

Iptables –t filter –A OUTPUT –d !192.168.0.254 –j DROP This denies all packets to every host except 192.168.0.254

Iptables –t filter –A INPUT –s 192.168.0.251 –I eth3 –j DROPThis rule denies all packets from 192.168.0.251 coming in to the eth3 interface.

Iptables –t filter –L INPUTThis rule is used to list the rules in a particular chain.

Iptables –FFor freshens Iptables.

APACHE WEB SERVER

Apache is RedHat’s standard web server. Apache is the most widely used web server. More then 60% sites are hosted on apache web

server. Apache provides very stable and scalable web server platform. Apache support virtual hosts in which multiple web sites may share the same web server.

Service profile: Apache

Type : System V-launched service Packages: httpd Daemons : httpd Script : httpd Ports : 80/tcp (http) , 443/tcp (https) Configuration : /etc/httpd/* , /var/www/*

Installing the Apache Server

1. Mount the Red Hat RPM source files for Apache. They may be located on CD or you may have copied them in a previous chapter to a network source.

2. Locate the Apache RPM packages: httpd, httpd-devel, redhat-config- httpd, mod_python, autoconf, automake, libtool, mod_perl, and mod_ssl. If you can’t find some of these packages; you may have to repeat steps 1–3 with a different Red Hat Installation CD.

3. Load the Apache RPM packages.

4. Use chkconfig to verify that Apache is not configured to start.

5. Now, use chkconfig to start Apache for runlevels 3 and 5.

6. Start Apache by hand by invoking the Apache management script (httpd) in /etc/rc.d/init.d.

7. Start a Web browser such as Mozilla or Konqueror. Point it at http://localhost. You should see the default Apache Web page for Red Hat Linux.

8. Close your Web browser.

Network File System (NFS)

NFS is the standard for sharing files and printers on a directory with Linux and UNIX computers. It was originally developed by Sun Microsystems in the mid-1980s. Linux has supported NFS (both as a client and a server) for years, and NFS continues to be popular in organizations with UNIX- or Linux-based networks.

Required PackagesTwo RPM packages are associated with NFS: portmap and nfs-utils. Use the rpm –q packagename command to check for these packages, which should provide a number of key files. The nfs-utils package includes:

o /etc/rc.d/init.d/nfs (start/stop script for NFS)o /etc/rc.d/init.d/nfslock (start/stop script for lockd and statd)o ¦/usr/share/doc/nfs-utils-version (documentation, mostly in HTML format)o Server daemons in /usr/sbin: rpc.mountd, rpc.nfsdo ¦Server daemons in /sbin: rpc.lockd, rpc.statdo Control programs in /usr/sbin: exportfs, nfsstat, nhfsstone, showmounto Status files in /var/lib/nfs: etab, rmtab, statd/state, xtab

The portmap package includes the following key files:

o /etc/rc.d/init.d/portmap (start/stop script)o /usr/share/doc/portmap-version (documentation)o Server daemon in /sbin: portmapo Control programs in /usr/sbin: pmap_dump, pmap_set

Service Profile: NFS

Type : System V-launched service Packages : nfs-utils

Daemons : nfsd, lockd ,rpciod , rpc.{mountd,rquotad,statd} Scripts : nfs , nfslock Ports : assigned by portmap (111) Configuration : /etc/exports

NFS Server & client

NFS SERVER (LINUX)

SWITCH

NFS CLIENT 1 NFS CLIENT 2 (LINUX) (UNIX)

Samba Server

Microsoft computers can share files and printers on a network through a facility called SMB, Server Message Block. This type of network communication over a Microsoft-based network is also known as NetBIOS over TCP/IP. Through the collective works of Andrew Tridgell and many others (in the Samba group), Linux systems provide transparent and reliable SMB support overTCP/IP via a package known as Samba. You can do four basic things with Samba:

Share a Linux directory tree with Windows computers. Share a Windows directory with Linux computers. Share a Linux printer with Windows computers.

Share a Windows printer with Linux computers.

It is easy to configure Samba to do a number of things on a Microsoft based network: ¦Participate in a Microsoft Windows 9x–style Workgroup or an NT/2000/XP Domain as a

client or a server. Act as a Primary or Backup Domain Controller. Share user home directories. Act as a WINS client or server. Link to or manage a workgroup browse service. Act as a Master Browser. Provide user/password and share security databases locally, from another Samba server, or

from a Microsoft Domain Controller. Configure local directories as shared SMB filesystems. Synchronize passwords between Windows and Linux systems. Download print drivers to Microsoft clients.

These are the four Samba RPM packages that you need: The Samba package includes the basic SMB server software for sharing files and printers. The Samba-common package contains common Samba configuration files. The Samba-client package provides the utilities needed to connect to shares from Microsoft

computers. The Samba-swat package includes the aforementioned SWAT configuration tool.

Service Profile : Samba

Type : System V-launched service

Package : samba, samba-common, samba-client Daemons : nmbd ,smbd Script : smb Ports : 137,138,139 Configuration : /etc/samba/smb.conf Related : samba-swat

SAMBA SERVER (LINUX)

PRINTER

SWITCH

LINUX WINDOW 98 WINDOW 2000 SERVER

SAMBA CLIENTS Fig: SAMBA SERVER SHAREING PRINTER,FILE & DIRECTORY

Network Designing & Implementation (Local Area Network):-

Hardware Requirement For Red Hat Linux Network Installation Pentium base Server with 64 MB RAM Hard disc drive of minimum 4.3 GB Ethernet Card (NIC) 10/100 MBPS 10 Nos Ethernet Hub 10/100 MBPS 12 Port 01 Nos UTP CAT 5e Cable 500 Meter (Approx) RJ-45 Connector 30 Nos

Software & Operating System Red Hat Linux 8.0 Professional Server 01 Nos Client Operating System 20 Nos

Network Installation & Implementation Red Hat Linux 8.0 Professional installation and Configuration (LAN/WAN)

NETWORK SETUP FOR ISP USING LINUX AS OS

Fig: Diagram for Network Setup for ISP

Linux Networking, for communication through a network the two basic requirements are the Media

and Rules, by media we mean the communication link (cables), hubs and switches. Media may be

wired or wireless, by rules we mean the set protocols used for communication. Hubs are dumb and not

an intelligent device, it works at the Physical layer whereas Switches are intelligent devices and works

at Data link layer. To obtain good performance we make use of Switches. In a Switch direct routing is

possible, the data packet is unicasted and not broadcasted, the packet doesn’t traverse to all the port but

direct connection is made via IP address.

Thus it have high performance, Switches maintain the IP address table for mapping process.

Rules or the protocol to be used depends on the OS on the end systems, if both the end systems have

MS-Windows then for small n/w we use Netbui protocol and for larger networks use of TCP/IP is

made. End systems having LINUX Operating System make use of TCP/IP protocol.

In the ISP Network diagram we can see a PRI line, it is a telephone line from BSNL taken by the ISP,

PRI stands for primary rate interface, it contains 32 channels out of which 2 are reserved for signaling

PSTN

USER

RAS

SWITCH

DNS DHCP LLM

ROUTER

INTERNET

RADIUS SERVER

SQUID PROXY SERVER

Internal Networking Node- PC

PRI LINE

MAIL SERVER

WEB SERVER

and the rest are to used for connection of the user with the ISP. One PRI line can server 30 users at a

time. Other than PRI line the ISP requires a certain bandwidth for getting connected to the internet &

this bandwidth is provided by the providers as Escotel, net4india, TATA, BSNL etc.

LLM, lease Line Modem, it is the hardware required to use the provided bandwidth. Radius Server is

the server used for billing and accounting of the users. The user authentication is also checked by this

server only. Squid Proxy Server is the LINUX based server & is used for internal networking.

RAS-Remote Access Server helps in connection establishment & provides a free port to the user to get

connected to the ISP.

The user dials up and the call goes to the PSTN which is routed to the RAS to which the user is

connected to the free port. The user is then authenticated via the Radius Server. The DHCP gives a

dummy IP address to the user and all the other servers are provided with the fixed real IP addresses.

The request from the user goes to the DNS which contain information of other server & DNS, the user

access the request using router with address from DNS.

Router

Switch

IBM Server Compaq Server HCL Squid Proxy Server

Fig: Network Diagram for Server Room of CTD

Squid Proxy Server: - Squid is a high –performance proxy caching server for Web Clients,

Supporting FTP, Gopher and HTTP data objects. Unlike traditional caching software, Squid

handles all requests in a single, on blocking, I/O driven process. Squid keeps meta data and

especially hot objects cached in RAM, Caches DNS lookups and implements negative caching of

failed requests. Squid consists of a main server program squid, a Domain Name System lookup

program, a program for retrieving FTP data and management and client tools.

1. I B M Server

Operating System: Windows 2000 Server, Running FTP Server

2. Compaq Server

Operating System: Redhat Linux 8.0 Professional Server

Installation and Configuration of Redhat Linux 8.0

Configuration of Firewall

Installation and Configuration of DNS Server

Internet Cloud

Installation & Configuration of Mail Server-mail, Linux base Mailing soln’s

Installation and Configuration of Apache Web Server

Configuring FTP Server & Telnet Services

3. HCL Squid Proxy Server

Operating System : Redhat Linux 8.0 Professional Server

Installation and Configuration of Redhat Linux 8.0 Professional

Installation and Configuration of Squid Proxy Server

BIBLIOGRAPHY

1. Red Hat Linux Essentials RH033.

2. Red Hat Linux System Administration RH133

3. Red Hat Linux Networking and Security Administration RH253.

Provided by REDHAT Corporation.

4. Redhat Linux 9.0 Unleased

5. Redhat Linux 9.0 Bible