ACKNOWLEDGEMENT

At the outset I submit over gratified thanks to Mr. Ravinder Singh Bhati, Head and director of Silicon Univ Jaipur with whose consent my training has accomplished.

I especially thank my guide Mr. Piyush Yauduvanshi, trainer of RHEL silicon univ, jaipur who has helped through the long and arduous task. He has been encouraging, patient, considerate and helpful all through. He proved to be a pain killer for all the trainees at silicon univ. I am highly indebted to Piyush sir.

My thanks to all the silicon univ staff members. The complete organization of silicon univ has been very supportive and cooperative throughout the training period.

I would like to give my special thanks to my friends Navin, Raees and sunny because whenever I needed a dose of encouragement, they somehow sended it and provide it just at the right time.

Finally I would like to acknowledge Mr. M. Ibrahim presently director of Open Linux, Jaipur to whom the credit of guiding us to undertake over training on RHEL.

                                                                                Anees Alam

                                                                                

PREFACE

As an integrated part of our B.E. syllabus in Computer Engineering we have to undergo the practical training of 45 days .I took my training at SILICON UNIV. Jaipur for 50   working days. It is situated in C-Scheme, Jaipur.

 I have studied about Red Hat Enterprise Linux in network services, system and security administration. the  report have consist various applications use in Linux  as setup of various kind of  networks, connect to the Internet, and configure a various types of servers such as Apache sever, Print server, Squid Server, Mail servers, DNS and   so on. The course also contain about the Gnome desktop environment, KDE environment, X window system.

 

 In this report we covered different type of networking services on Red Hat Enterprise Linux as Server side setup configuration, and basic administration of common networking services: DNS, NIS, APACHE, SMB, DHCP, SEND MAIL, and FTP. It also covers different type of security policy, file system security, kernel security and basic element of firewall.

                                        CONTENT

Introduction to Linux

Salient Features of Linux

Linux Installation

Linux Kernel & Shell

Linux file System

X Windows System

Linux Networking

Linux as Router

Linux as Firewall

DNS Server

DHCP Server

Apache Web Server

Network File System

Samba Server

Network Setup for ISP using Linux AS OS

Introduction to Project of Diskless workstation

                             

COMPANY PROFILE

   

   SILICON COMNET was formed in 1995 with a clear brief to design, implement & support high technology related products in the field of data communication telecommunication networking and operating system. With national wide alliances with principles like LUCENT, Convergent Communications, Intel, Cisco System, Motorola and Sun System. Silicon Comnet has developed expertise in following divisions.

With a massive clients like Indian Army, Essar Cell phone, Spice Telecom India, Indian Air-force, Smithline Beecham, Care India, IL&FS, Hoechst, State Bank of India, TCS, Jindal, Bombay Stock Exchange, Dolat capital, J. K. Group and many others, Silicon Comnet today is a National Network Integration Giant.

The education division of Silicon Comnet is branded as SILICON UNIV TM, started in order to cater technology programs for their customers, partners & in-house team. Today with State of art infrastructure and facilities, SILICON UNIV TM has trained over a thousand people across India and overseas in networking and system administration and operates today with a prime mandate of  “Implement the best and bag the Best” of imparting quality training on

 

  It deals in Network solution, LAN -WAN solution, Firewall, Mail server, Web server, Radius, Squid, proxy server. They also deal in server maintenance & installing heterogeneous network.

  In today’s economy, finding ways to leverage technology and services to be more efficient, reduce costs, and develop flexibility to respond rapidly to the changing market is critical to survival. SILICON UNIV, Red Hat channel partner offers a set of solutions built on the benefits of an open source platform. Red Hat solutions include a core set of open source product offerings, a comprehensive end to end set of professional services, and Red Hat Network for more effective deployment and management of your system. SILICON UNIV is Market-acknowledged and unmatched technical expertise for Red Hat LINUX.

  They are Red Hat Professional Consulting and provide a vendor-neutral approach. The consulting approach is multi-platform, integrated, reliable network infrastructure solutions based on individual client needs.

  Red Hat Network is the internet-based system support and management service for Red Hat Linux networks. It provides a platform for Linux System management that improves system reliability and security while saving time and increasing productivity of technical administrators.

  While Red Hat has the capability to provide a comprehensive outsourced support solutions, many customers may seek a blended approach to support and management of their open source solutions. For those who demand in-house expertise, Red Hat Global Learning Service provides the premier training curriculums and performance-based certification (RHCE) for open source platform and application development and administration.

  Red Hat develops, deploys, and manages solutions built on an open source   Platform, including the Red Hat Linux Operating System for mainframes, Servers, workstations, and embedded services. The company offers a range of open source development tools, a suite to end-to-end professional services, including Consulting, engineering, enterprise support and global learning with growing popularity and acceptance of Linux in the govt. sector.  The SILICON UNIV as Red Hat Channel Partner implemented the Linux successfully.

 

 

                      

                     

                                   

 

                   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

   Advantages of Linux:-

  • Virus proof

  • Advanced OS

  • Crash proof

  • Economical

  • Secured

  • Fully supported

  • 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

  1. CD-ROM
  2. NFS
  3. FTP
  4. HTTP
  5. HARD DISK
  6. Through kickstart method

Types of Boot loader

  1. GRUB
  2. LILO

    Hard Disk Partitioning Method

  1. Disk druid
  2. fdisk

    Type of X-Window System (Desktop)

  1. GNOME – GNU Network Object Model Environment
  2. 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:

Types of Shell in Linux:

 

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 SUPPORTED FILE SYSTEMS

File system

           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 File system Hierarchy Standard (FHS).

File system 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 (accept 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 Star Office 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.

IMPORTANT FILE TYPES

# Octothorpe.

$HOME

Environment variable that points to your login directory.

$PATH

Pathname environment variable.

$PATH

The shell environment variable that contains a set of directories to be searched for UNIX commands.

.1

Files with this extension contain manual page entries. The actual extension can be any value between 1 and 9 and can have an alphabetic suffix (.3x, .7, and so on).

.ag: Applixware graphics file.

.as: Applixware spreadsheet file.

.aw: Applixware word processing file.

.bmp: Bitmap graphics file.

.c: C source file.

.C:C++ source file.

.cc:C++ source file.

.conf: Configuration file.

.cxx :C++ source file.

.db: Database file.

.dvi: Device-independent TeX output.

.gif: GIF graphics file.

.gz: File compressed using the GNU gzip utility.

.h: C header file.

.html: HTML document.

.jpg: JPEG graphics file.

.m: Objective C source file.

.o: Compiled object file.

.p: Pascal language source file.

.pbm: Portable bitmap graphics file.

.pdf: Adobe Acrobat files.

.ps: PostScript file

.s: Assembler file.

.tar: tar file.

.tgz: Gzipped tar file.

.tif: TIFF graphics file.

.txt: Text document.

.Z:  File compressed using the compress command.

LOGICAL VOLUME MANAGER (LVM)

As a very special treat, LVM can even make 'snapshots' of itself which enable you to make backups of a non-moving target. We return to this exciting possibility, which has lots of other real-world applications, later on.

In the next section we explain the basics of LVM, and the multitude of abstractions it uses. Historically, a partition size is static. This requires a system installer to have to consider not the question of "how much data will store on this partition", but rather "how much data will *EVER* store on this partition". When a user runs out of space on a partition, they either has to re-partition (which may involve an entire operating system reload) or use kludges such as symbolic links.

The notion that a partition was a sequential series of blocks on a physical disc has since evolved. Most Unix-like systems now have the ability to break up physical discs into some number of units. Storage units from multiple drives can be pooled into a "logical volume", where they can be allocated to partitions. Additionally, units can be added or removed from partitions as space requirements change.

This is the basis of a Logical Volume Manager (LVM).

For example, say that you have a 1GB disc and you create the "/home" partition using 600MB. Imagine that you run out of space and decide that you need 1GB in "/home". Using the old notion of partitions, you'd have to have another drive at least 1GB in size. You could then add the disc, create a new /home, and copy the existing data over.

However, with an LVM setup, you could simply add a 400MB (or larger) disc, and add its storage units to the "/home" partition. Other tools allow us to resize an existing file-system, so we simply resize it to take advantage of the larger partition size and we're back in business.

The physical media 

We should take the word 'physical' with a grain of salt, though we will initially assume it to be a simple hard disk, or a partition. Examples, /dev/hda, /dev/hda6, /dev/sda. You can turn any consecutive number of blocks on a block device into a...

Physical Volume (PV) 

A PV is nothing more than a physical medium with some administrative data added to it - once you have added this, LVM will recognize it as a holder of...

Physical Extents (PE) 

Physical Extents are like really big blocks, often with a size of megabytes. PEs can be assigned to a...

Volume Group 

A VG is made up of a number of Physical Extents (which may have come from multiple Physical Volumes or hard drives). While it may be tempting to think of a VG as being made up of several hard drives (/dev/hda and /dev/sda for example), it's more accurate to say that it contains PEs which are provided by these hard drives.

>From this Volume Group, PEs can be assigned to a...

Logical Volume (LV) 

A Logical Volume is the end result of our work, and it's there that we store our information. This is equivalent to the historic idea of partitions.

As with a regular partition, on this Logical Volume you would typically build a...

Filesystem 

This filesystem is whatever we want it to be: the standard ext2, ReiserFS, NWFS, XFS, JFX, NTFS, etc... To the linux kernel, there is no difference between a regular partition and a Logical Volume.

.

A Physical Volume, containing Physical Extents:

  +----- [Physical Volume] ------+

  | PE | PE | PE | PE | PE | PE  |

  +------------------------------+

A Volume Group, containing 2 Physical Volumes (PVs) with 6 Physical Extents:

  +------ [Volume Group] -----------------+

  | +--[PV] --------+ +--[PV] ---------+  |

  | | PE | PE | PE | | PE | PE | PE |  |

  |  +--------------+  +---------------+  |

  +---------------------------------------+

We now further expand this:

  +------ [Volume Group] -----------------+

  | +--[PV] --------+ +--[PV] ---------+  |

  | | PE | PE | PE | | PE | PE | PE |  |

  |  +--+---+---+---+  +-+----+----+---+  |

  |     |   |   | +-----/     |    |      |

  |     |   |   | |           |    |      |

  |   +-+---+---+-+      +----+----+--+   |

  |   | Logical   |      |   Logical  |   |

  |   | Volume    |      |   Volume   |   |

  |   |           |      |            |   |

  |   | /home     |      |    /var    |   |

  |   +-----------+      +------------+   |

  +---------------------------------------+

This shows us two filesystems, spanning two disks. The /home filesystem contains 4 Physical Extents, the /var filesystem 2.

     

                                      X WINDOW SYSTEM

                           

                                        

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:-

 

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.  

 

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 Command

  1.  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

       

  1.   Traceroute – Shows network path between local and remote systems.                            Useful for pinpointing network congestion.

                                    Example: traceroute www.redhat.com

       

  1.    Netstat –   Lists network statistics and parameters, including Network                          Connection, Routing table, Interface statistics.

        Example: netstat –rn

                                Or            netstat –a

               

  1.    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

  1.   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 addresses: 0x10a0

# /sbin/ifconfig eth0 207.174.142.142

The 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 addresses: 0x10a0

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:

  1. Configure the network cards
  2. Run the netconf command
  3. Select the Routing & Gateway option
  4. Provide the required IP address
  5. Select Enable Routing option.
  6. Accept the configuration
  7. Restart the network service

CLASS A            10.0.0.2       10.0.0.3

NETWORK

                     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

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

Packet filter: - Screening Router

Filters Ip packets

Route between networks

Protocol independent

Only filters packet header

Minimal hardware needs

Work on transport layer

           

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 DROP

This rule denies all packets from 192.168.0.251 coming in to the eth3 interface.

Iptables –t filter –L INPUT

This rule is used to list the rules in a particular chain.

Iptables –F

For freshens Iptables.

                             

   

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

        

Master DNS Server- contains the master copy of data for a zone.

Slave DNS Server - provides an automatic backup to the master name server.

Caching-only Server - When a request is make for a Web page such as www.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  

.edu

.gov

.com

.org

nasa.gov

Top level Domain

Second level Domain

poornima.org

Domain Name System

   

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 SERVER

DHCP 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 3

192.168.0.18                                 192.168.0.19                  192.168.0.20        

                 DHCP SERVER PROVIDE IP ADDRESS DYNAMICALLY

           

  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.   Start a Web browser such as Mozilla or Konqueror. Point it at http://localhost.
  7. 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 Packages

Two 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:

/etc/rc.d/init.d/nfs (start/stop script for NFS)

/etc/rc.d/init.d/nfslock (start/stop script for lockd and statd)

¦/usr/share/doc/nfs-utils-version (documentation, mostly in HTML format)

Server daemons in /usr/sbin: rpc.mountd, rpc.nfsd

¦Server daemons in /sbin: rpc.lockd, rpc.statd

Control programs in /usr/sbin: exportfs, nfsstat, nhfsstone, showmount

Status files in /var/lib/nfs: etab, rmtab, statd/state, xtab

The portmap package includes the following key files:

/etc/rc.d/init.d/portmap (start/stop script)

/usr/share/doc/portmap-version (documentation)

Server daemon in /sbin: portmap

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 over TCP/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 file systems

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

        

               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)

           

BIBLIOGRAPHY

 As per the need of my project of networking on Linux operating system, I required information regarding various tools used in networking.  Therefore I have gone through several books for above information’s. My project coordinator has suggested me to go through some books whose list is as Follows:-

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

6. Linux Complete Command Reference

7.

Websites:-

www.in.redhat.com

www.ltsp.org

www.wilieystem.com

www.linux.org

www.disklessworkstation.com

SOME IMPORTANT TERMS IN LINUX

AT&T UNIX

Original version of UNIX developed at AT&T Bell Labs, later known as UNIX Systems Laboratories. Many current versions of UNIX are descendants; even BSD UNIX was derived from early AT&T UNIX.

Attribute

The means of describing objects the attributes for a ball might be rubber, red, and 3 cm in diameter. The behavior of the ball might be how high it bounces when thrown. Attribute is another name for the data contained within an object (class).

Awk

Programming language developed by A.V. Aho, P.J. Weinberger, and Brian W. Kernighan. The language is built on C syntax, includes the regular expression search facilities of grep, and adds in the advanced string and array handling features that are missing from the C language. nawk, gawk, and POSIX awk are versions of this language.

Background

Processes usually running at a lower priority and with their input disconnected from the interactive session any input and output are usually directed to a file or other process.

Background process

An autonomous process that runs under UNIX without requiring user interaction

Backup

The process of storing the UNIX system, applications, and data files on removable media for future retrieval.

Bash

Stands for GNU Bourne Again Shell and is based on the Bourne shell, sh, the original command interpreter.

biff

Background mail notification utility

bison

GNU parser generator (yacc replacement)

Block-special

A device file that is used to communicate with a block-oriented I/O device Disk and tape drives are examples of block devices. The block-special file refers to the entire device. You should not use this file unless you want to ignore the directory structure of the device (that is, if you are coding a device driver).

Boot or boot up

The process of starting the operating system (UNIX)

Bourne shell

The original standard user interface to UNIX that supported limited programming capability

BSD

Berkeley Software Distribution

BSD UNIX

Version of UNIX developed by Berkeley Software Distribution and written at University of California, Berkeley

Bug

An undocumented program feature

C

Programming language developed by Brian W. Kernighan and Dennis M. Ritchie. The C language is highly portable and available on many platforms including mainframes, PCs, and, of course, UNIX systems.

C shell

A user interface for UNIX written by Bill Joy at Berkeley It features C programming-like syntax

CAD

Computer-aided design.

Cast

Programming constructs to force type conversion.

cat

Concatenate files command.

CD-ROM

Compact Disk-Read Only Memory Computer-readable data stored on the same physical form as a musical CD Large capacity, inexpensive, slower than a hard disk, and limited to reading. There are versions that are writable (CD-R, CD Recordable) and other formats that can be written to once or many times.

Character special

A device file that is used to communicate with character-oriented I/O devices like terminals, printers, or network communications lines All I/O access is treated as a series of bytes (characters).

Characters, alphabetic

The letters A through Z and a through z

Characters, alphanumeric

The letters A through Z and a through z, and the numbers 0 through 9

Characters, control

Any nonprintable characters the characters are used to control devices, separate records, and eject pages on printers.

Characters, numeric

The numbers 0 through 9

Characters, special

Any of the punctuation characters or printable characters that is not alphanumeric. Include the space, comma, period, and many others.

Child process

See sub process.

Child shell

See sub shell.

Class

A model of objects that have attributes (data) and behavior (code or functions). It is also viewed as a collection of objects in their abstracted form.

Command-line editing

UNIX shells support the ability to recall a previously entered command, modify it, and then execute the new version. The command history can remain between sessions (the commands you did yesterday can be available for you when you log in today). Some shells support a command-line editing mode that uses a subset of the VI, emacs, or gmacs editor commands for command recall and modification.

Command-line history

See command-line editing.

Command-line parameters

Used to specify parameters to pass to the execute program or procedure. Also known as command-line arguments

Configuration files

Collections of information used to initialize and set up the environment for specific commands and programs. Shell configuration files set up the user’s environment.

Configuration files, shell

For Bourne shell: /etc/profile and $HOME/.profile.
For Korn and pdksh shells: /etc/profile, $HOME/.profile, and ENV= file.
For C and tcsh shells: /etc/.login, /etc/cshrc, $HOME/.login, $HOME/.cshrc, and $HOME/.logout. Older versions might not support the first two files listed.
For bash: /etc/profile/, $HOME/.bash_profile, $HOME/.bash_login, $HOME/.profile, $HOME/.bashrc, and ~/.bash_logout.

CPU

Central Processing Unit The primary “brain” of the computer—the calculation engine and logic controller.

Daemon

A system-related background process that often runs with the permissions of root and services requests from other processes

DARPA

(U.S. Department of) Defense Advanced Research Projects Agency Funded development of TCP/IP and ARPAnet (predecessor of the Internet)

Database server

See server, database.

Device file

File used to implement access to a physical device. This provides a consistent approach to access of storage media under UNIX; data files and devices (like tapes and communication facilities) are implemented as files. To the programmer, there is no real difference.

Directory

A means of organizing and collecting files together. The directory itself is a file that consists of a list of files contained within it. The root (/) directory is the top level and every other directory is contained in it (directly or indirectly). A directory might contain other directories, known as subdirectories.

Directory navigation

The process of moving through directories is known as navigation. Your current directory is known as the current working directory. Your login directory is known as the default or home directory. Using the cd command, you can move up and down through the tree structure of directories.

DNS

Domain Name Server Used to convert between the names of a machine on the Internet (name.domain.com) to the numeric address (123.45.111.123).

DOS

Disk Operating System Operating system that is based on the use of disks for the storage of commands it is also a generic name for MS-DOS and PC-DOS on the personal computer. MS-DOS is the version Microsoft sells; PC-DOS is the version IBM sells. Both are based on Microsoft code.

Double

Double-precision floating point

Dpi

Dots per inch

EBCDIC

Extended Binary Coded Decimal Interchange Code The code used to represent characters in memory for mainframe computers.

ed

A common tool used for line-oriented text editing.

elm

Interactive mail program.

emacs

A freely available editor now part of the GNU software distribution. Originally written by Richard M. Stallman at MIT in the late 1970s, it is available for many platforms. It is extremely extensible and has its own programming language; the name stands for editing with macros.

email

Messages sent through an electronic medium instead of through the local postal service. There are many proprietary email systems that are designed to handle mail within a LAN environment; most of these are also able to send over the Internet. Most Internet (open) email systems make use of MIME to handle attached data (which can be binary).

Encapsulation

The process of combining data (attributes) and functions (behavior in the form of code) into an object the data and functions are closely coupled within an object. Instead of all programmers being able to access the data in a structure their own way, they have to use the code connected with that data. This promotes code reuse and standardized methods of working with the data.

Environment variables

See variables, environmental.

Ethernet

A networking method where the systems are connected to a single shared bus and all traffic is available to every machine. The data packets contain an identifier of the recipient, and that is the only machine that should process that packet.

Expression

A constant, variable, or operands and operators combined. Used to set a value, perform a calculation, or set the pattern for a comparison (regular expressions).

FIFO

First In, First out See pipe, named

File

Collection of bytes stored on a device (typically a disk or tape). Can be source code, executable binaries or scripts, or data

File compression

The process of applying mathematical formulas to data, typically resulting in a form of the data that occupies less space a compressed file can be uncompressed, resulting in the original file. When the compress/uncompress process results in exactly the same file as was originally compressed, it is known as lossless. If information about the original file is lost, the compression method is known as lossy. Data and programs need lossless compression; images and sounds can stand lossy compression.

File, indexed

A file based on a file structure where data can be retrieved based on specific keys (name, employee number, and so on) or sequentially. The keys are stored in an index. This is not directly supported by the UNIX operating system; usually implemented by the programmer or by using tools from an ISV. A typical form is known as ISAM.

File, line sequential

See file, text.

File, sequential

This phrase can mean either a file that can only be accessed sequentially (not randomly), or a file without record separators (typically fixed length, but UNIX does not know what that length is and does not care).

File, text

A file with record separators Can be fixed or variable length; UNIX tools can handle these files because the tools can tell when the record ends (by the separator).

Filename

The name used to identify a collection of data (a file). Without a pathname, it is assumed to be in the current directory.

Filename generation

The process of the shell interpreting metacharacters (wildcards) to produce a list of matching files this is referred to as filename expansion or globbing

Filename, fully qualified

The name used to identify a collection of data (a file) and its location. It includes both the path and name of the file; typically, the pathname is fully specified (absolute). See also pathname and pathname, absolute.

filesystem

A collection of disk storage that is connected (mounted) to the directory structure at some point (sometimes at the root). Filesystems are stored in a disk partition and are sometimes referred to as being the disk partition.

finger

User information lookup program.

Firewall

A system used to provide a controlled entry point to the internal network from the outside (usually the Internet). This is used to prevent outside or unauthorized systems from accessing systems on your internal network. The capability depends on the individual software package, but the features typically include filter packets and filter datagrams, system (name or IP address) aliasing, and rejecting packets from certain IP addresses. In theory, it provides protection from malicious programs or people on the outside. It can also prevent internal systems from accessing the Internet on the outside. The name comes from the physical barrier between connected buildings or within a single building that is supposed to prevent fire from spreading from one to another.

flags

See options.

float

Single-precision floating point

foreground

Programs running while connected to the interactive session.

fseek

Internal function used by UNIX to locate data inside a file or filesystem. ANSI standard fseek accepts a parameter that can hold a value of +2 to -2 billion. This function, used by the operating system, system tools, and application programs, is the cause of the 2GB file and filesystem size limitation on most systems. With 64-bit operating systems, this limit is going away.

FSF

Free Software Foundation.

FTP

File Transfer Protocol or File Transfer Program. A system-independent means of transferring files between systems connected via TCP/IP. Ensures that the file is transferred correctly, even if there are errors during transmission Can usually handle character set conversions (ASCII/EBCDIC) and record terminator resolution (linefeed for UNIX, carriage return and linefeed for MS/PC-DOS).

Gateway

A combination of hardware, software, and network connections that provides a link between one architecture and another typically, a gateway is used to connect a LAN or UNIX server with a mainframe (that uses SNA for networking, resulting in the name SNA gateway). A gateway can also be the connection between the internal and external network (often referred to as a firewall). See also firewall.

GID

Group ID number

globbing

See filename generation.

GNU

GNU stands for GNU’s Not UNIX, and is the name of free useful software packages commonly found in UNIX environments that are being distributed by the GNU project at MIT, largely through the efforts of Richard Stallman. The circular acronym name (“GNU” containing the acronym GNU as one of the words it stands for) is a joke on Richard Stallman’s part. One of the textbooks on operating system design is titled XINU: XINU Is Not UNIX and GNU follows in that path.

GPL

GNU General Public License.

grep

A common tool used to search a file for a pattern. egrep and fgrep are newer versions. egrep allows the use of extended (hence the e prefix) regular expressions; fgrep uses limited expressions for faster (hence the f prefix) searches.

GUI

Graphical user interface

Here document

The << redirection operator, known as here document, allows keyboard input (stdin) for the program to be included in the script.

HTML

Hypertext Markup Language Describes World Wide Web pages. It is the document language that is used to define the pages available on the Internet through the use of tags. A browser interprets the HTML to display the desired information.

i-node

Used to describe a file and its storage the directory contains a cross-reference between the i-node and pathname/filename combination. Also known as inode A file’s entry in disk data structure (ls -i).

I-Phone

Internet Phone. This is a method of transmitting speech long distances over the Internet in near real-time. Participants avoid paying long distance telephone charges. They still pay for the call to their ISP and the ISP’s service charges.

ICCCM

Inter-Client Communications Conventions Manual.

ICMP

Internet Control Message Protocol. Part of TCP/IP that provides network layer management and control.

imake

C preprocessor interface to make utility.

inheritance

A method of object-oriented software reuse in which new classes are developed based on existing ones by using the existing attributes and behavior and adding on to them. If the base object is automobiles (with attributes of engine and four wheels and tires; behavior of acceleration, turning, deceleration), a sports car would modify the attributes: engine might be larger or have more horsepower than the default, the four wheels might include alloy wheels and high-speed–rated tires; the behavior would also be modified: faster acceleration, tighter turning radius, faster deceleration.

inode

See i-node.

int

Integer.

Internet

A collection of different networks that provide the ability to move data between them. It is built on the TCP/IP communications protocol. Originally developed by DARPA, it was taken over by NSF, and has now been released from governmental control.

Internet Service Provider

The people that connect you to the Internet.

IRC

Internet relay chat. A server-based application that allows groups of people to communicate simultaneously through text-based conversations. IRC is similar to Citizen Band radio or the chat rooms on some bulletin boards. Some chats can be private (between invited people only) or public (where anyone can join in). IRC now also supports sound files as well as text; it can also be useful for file exchange.

ISAM

Indexed Sequential Access Method. On UNIX and other systems, ISAM refers to a method for accessing data in a keyed or sequential way. The UNIX operating system does not directly support ISAM files; they are typically add-on products.

ISO

International Standards Organization.

ISP

See Internet Service Provider.

ISV

Independent Software Vendor. Generic name for software vendors other than your hardware vendor.

K&R

Kernighan and Ritchie.

kernel

The core of the operating system that handles tasks like memory allocation, device input and output, process allocation, security, and user access. UNIX tends to have a small kernel when compared to other operating systems.

keys, control

These are keys that cause some function to be performed instead of displaying a character. These functions have names: The end-of-file key tells UNIX that there is no more input; it is usually Ctrl+D.

keys, special

See keys, control.

Korn shell

A user interface for UNIX with extensive scripting (programming) support. Written by David G. Korn. The shell features command-line editing and will also accept scripts written for the Bourne shell.

LAN

Local Area Network. A collection of networking hardware, software, desktop computers, servers, and hosts all connected together within a defined local area. A LAN could be an entire college campus.

limits

See quota.

link file

File used to implement a symbolic link producing an alias on one filesystem for a file on another. The file contains only the fully qualified filename of the original (linked-to) file.

link, hard

Directory entry that provides an alias to another file within the same filesystem. Multiple entries appear in the directory (or other directories) for one physical file without replication of the contents.

link, soft

See link, symbolic.

link, symbolic

Directory entry that provides an alias to another file that can be in another filesystem. Multiple entries appear in the directory for one physical file without replication of the contents. Implemented through link files; see also link file.

LISP

List Processing Language.

login

The process with which a user gains access to a UNIX system. This can also refer to the user ID that is typed at the login prompt.

lp

Line printer.

lpc

Line printer control program.

lpd

Line printer daemon.

lpq

Printer spool queue examination program.

lprm

Printer spool queue job removal program.

ls

List directory(s) command.

man page

Online reference tool under UNIX that contains the documentation for the system—the actual pages from the printed manuals. It is stored in a searchable form for improved ability to locate information.

manual page

See man page.

memory, real

Theamount of storage that is being used within the system (silicon; it used to be magnetic cores).

memory, virtual

Memory that exists but you cannot see. Secondary storage (disk) is used to allow the operating system to enable programs to use more memory than is physically available.
Part of a disk is used as a paging file and portions of programs and their data are moved between it and real memory. To the program, it is in real memory. The hardware and operating system performs translation between the memory address the program thinks it is using and where it is actually stored.

metacharacter

A printing character that has special meaning to the shell or another command. It is converted into something else by the shell or command; the asterisk (*) is converted by the shell to a list of all files in the current directory.

MIME

Multipurpose Internet Mail Extensions. A set of protocols or methods of attaching binary data (executable programs, images, sound files, and so on) or additional text to email messages.

motd

Message of the day.

MPTN

MultiProtocol Transport Network IBM networking protocol to connect mainframe to TCP/IP network.

Mrm

Motif resource manager.

mtu

Maximum transmission unit.

mwm

Motif window manager.

Netnews

This is a loosely controlled collection of discussion groups. A message (similar to an e-mail) is posted in a specific area, and then people can comment on it, publicly replying to the same place (posting a response) for others to see. A collection of messages along the same theme is referred to as a thread. Some of the groups are moderated, which means that nothing is posted without the approval of the owner. Most are not, and the title of the group is no guarantee that the discussion will be related. The official term for this is Usenet news.

NFS

Network File System. Means of connecting disks that are mounted to a remote system to the local system as if they were physically connected.

NIS

Network Information Service. A service that provides information necessary to all machines on a network, such as NFS support for hosts and clients, password verification, and so on.

NNTP

Netnews Transport Protocol Used to transmit Netnews or Usenet messages over top of TCP/IP. See Netnews for more information on the messages transmitted.

Null Statement

A program step that performs no operation but to hold space and fulfill syntactical requirements of the programming language. Also known as a NO-OP for no-operation performed.

object

An object in the truest sense of the word is something that has physical properties, like automobiles, rubber balls, and clouds. These things have attributes and behavior. They can be abstracted into data (attribute) and code (behavior). Instead of just writing functions to work on data, they are encapsulated into a package that is known as an object.

operator

Metacharacter that performs a function on values or variables. The plus sign (+) is an operator that adds two integers.

options

Program- or command-specific indicators that control behavior of that program. Sometimes called flags. The -a option to the ls command shows the files that begin with . (such as .profile, .kshrc, and so on). Without it, these files would not be shown, no matter what wildcards were used. These are used on the command line. See also parameters.

OSF

Open Software Foundation.

parameters

Data passed to a command or program through the command line. These can be options (see options) that control the command or arguments that the command works on. Some have special meaning based on their position on the command line.

parent process

Process that controls another often referred to as the child process or subprocess. See also process.

parent process identifier

Shown in the heading of the ps command as PPID. The process identifier of the parent process. See also parent process.

parent shell

Shell (typically the login shell) that controls another, often referred to as the child shell or subshell. See also shell.

password

The secure code that is used in combination with a user ID to gain access to a UNIX system.

pathname

The means used to represent the location of a file in the directory structure. If you do not specify a pathname, it defaults to the current directory.

pathname, absolute

The means used to represent the location of a file in a directory by specifying the exact location, including all directories in the chain including the root.

pathname, relative

The means used to represent the location of a file in a directory other than the current by navigating up and down through other directories using the current directory as a base.

PDP

Personal Data Processor Computers manufactured by Digital Equipment Corporation. UNIX was originally written for a PDP-7 and gained popularity on the PDP-11. The entire series were inexpensive minicomputers popular with educational institutions and small businesses.

Perl

Programming language developed by Larry Wall. (Perl stands for “Practical Extraction and Report Language” or “Pathologically Eclectic Rubbish Language”; both are equally valid.) The language provides all of the capabilities of awk and sed, plus many of the features of the shells and C.

permissions

When applied to files, they are the attributes that control access to a file. There are three levels of access: Owner (the file creator), Group (people belonging to a related group as determined by the system administrator), and Other (everyone else). The permissions are usually r for read, w for write, and x for execute. The execute permissions flag is also used to control who may search a directory.

PGP

Pretty Good Privacy encryption system.

pine

Interactive mail program.

pipe

A method of sending the output of one program (redirecting) to become the input of another. The pipe character (|) tells the shell to perform the redirection.

pipe file

See pipe, named.

pipe, named

An expanded function of a regular pipe (redirecting the output of one program to become the input of another). Instead of connecting stdout to stdin, the output of one program is sent to the named pipe and another program reads data from the same file. This is implemented through a special file known as a pipe file or FIFO. The operating system ensures the proper sequencing of the data. Little or no data is actually stored in the pipe file; it just acts as a connection between the two.

polymorphism

Allows code to be written in a general fashion to handle existing and future related classes. Properly developed, the same behavior can act differently depending on the derived object it acts on. With an automobile, the acceleration behavior might be different for a station wagon and a dragster, which are subclasses of the superclass automobile. The function would still be accelerate(), but the version would vary (this might sound confusing, but the compiler keeps track and figures it all out).

POSIX

Portable Operating System Interface, UNIX. POSIX is the name for a family of open system standards based on UNIX. The name has been credited to Richard Stallman. The POSIX Shell and Utilities standard developed by IEEE Working Group 1003.2 (POSIX.2) concentrates on the command interpreter interface and utility programs.

PostScript

Adobe Systems, Inc. printer language.

PPP

Point-to-Point Protocol. Internet protocol over serial link (modem).

pppd

Point-to-Point-Protocol daemon.

printcap

Printer capability database.

process

A discrete running program under UNIX. The user’s interactive session is a process. A process can invoke (run) and control another program that is then referred to as a subprocess. Ultimately, everything a user does is a subprocess of the operating system.

process identifier

Shown in the heading of the ps command as PID. The unique number assigned to every process running in the system.

pwd

Print working directory command.

quota

General description of a system-imposed limitation on a user or process. It can apply to disk space, memory usage, CPU usage, maximum number of open files, and many other resources.

quoting

The use of single and double quotes to negate the normal command interpretation and concatenate all words and whitespace within the quotes as a single piece of text.

RCS

Revision Control System.

redirection

The process of directing a data flow from the default. Input can be redirected to get data from a file or the output of another program. Normal output can be sent to another program or a file. Errors can be sent to another program or a file.

regular expression

A way of specifying and matching strings for shells (filename wildcarding), grep (file searches), sed, and awk.

reserved word

A set of characters that are recognized by UNIX and related to a specific program, function, or command.

RFC

Request For Comment Document used for creation of Internet- and TCP/IP-related standards.

rlogin

Remote Login. Gives the same functionality as telnet, with the added functionality of not requiring a password from trusted clients, which can also create security concerns (see also telnet).

root

The user that owns the operating system and controls the computer. The processes of the operating system run as though a user, root, signed on and started them. Root users are all- powerful and can do anything they want. For this reason, they are often referred to as superusers. Root is also the very top of the directory tree structure.

routing

The process of moving network traffic between two different physical networks; also decides which path to take when there are multiple connections between the two machines. It might also send traffic around transmission interruptions.

RPC

Remote Procedural Call. Provides the ability to call functions or subroutines that run on a remote system from the local one.

RPM

Red Hat Package Manager.

script

A program written for a UNIX utility including shells, awk, Perl, sed, and others. See also shell scripts.

SCSI

Small Computer System Interface.

sed

A common tool used for stream text editing, having ed-like syntax.

server, database

A system designated to run database software (typically a relational database like Oracle, SQL Server, Sybase, or others). Other systems connect to this one to get the data (client applications).

SGID

Set group ID.

shell

The part of UNIX that handles user input and invokes other programs to run commands. Includes a programming language. See also Bourne shell, C shell, Korn shell, tcsh, and bash.

shell environment

The shell program (Bourne, Korn, C, tcsh, or bash), invocation options and preset variables that define the characteristics, features, and functionality of the UNIX command-line and program execution interface.

shell or command prompt

The single character or set of characters that the UNIX shell displays for which a user can enter a command or set of commands.

shell scripts

A program written using a shell programming language like those supported by Bourne, Korn, or C shells.

signal

A special flag or interrupt that is used to communicate special events to programs by the operating system and other programs.

SLIP

Serial Line Internet Protocol. Internet over a serial line (modem). The protocol frames and controls the transmission of TCP/IP packets of the line.

SNA

System Network Architecture. IBM networking architecture.

stderr

The normal error output for a program that is sent to the screen by default. Can be redirected to a file.

stdin

The normal input for a program, taken from the keyboard by default. Can be redirected to get input from a file or the output of another program.

stdout

The normal output for a program that is sent to the screen by default. Can be redirected to a file or to the input of another program.

sticky bit

One of the status flags on a file that tells UNIX to load a copy of the file into the page file the first time it is executed. This is done for programs that are commonly used so the bytes are available quickly. When the sticky bit is used on frequently used directories, it is cached in memory.

stream

A sequential collection of data. All files are streams to the UNIX operating system. To it, there is no structure to a file; that is something imposed by application programs or special tools (ISAM packages or relational databases).

subdirectory

See directory.

subnet

A portion of a network that shares a common IP address component. Used for security and performance reasons.

subprocess

Process running under the control of another, often referred to as the parent process. See also process.

subshell

Shell running under the control of another, often referred to as the parent shell (typically the login shell). See also shell.

SUID

Set user ID.

superuser

Usually the root operator.

sysadmin

Burnt-out root operator (system administrator).

system administrator

The person who takes care of the operating system and user administrative issues on UNIX systems. Also called a system manager, although that term is much more common in DEC VAX installations.

system manager

See system administrator.

system programmer

See system administrator.

tar

Tape archiving utility.

TCP

Transmission Control Protocol.

TCP/IP

Transport Control Protocol/Internet Protocol. The pair of protocols and also generic name for suite of tools and protocols that forms the basis for the Internet. Originally developed to connect systems to the ARPAnet.

tcsh

A C shell-like user interface featuring command-line editing.

telnet

Remote login program.

Telnet

Protocol for interactive (character user interface) terminal access to remote systems. The terminal emulator that uses the Telnet protocol is often known as telnet or tnvt100.

termcap

Terminal capability database.

terminal

A hardware device, normally containing a cathode ray tube (screen) and keyboard for human interaction with a computer system.

text processing languages

A way of developing documents in text editors with embedded commands that handle formatting. The file is fed through a processor that executes the embedded commands, producing a formatted document. These include roff, nroff, troff, RUNOFF, TeX, LaTeX, and even the mainframe SCRIPT.

TFTP

Trivial File Transfer Protocolor Trivial File Transfer Program. A system-independent means of transferring files between systems connected via TCP/IP. It is different from FTP in that it does not ensure that the file is transferred correctly, does not authenticate users, and is missing a lot of functionality (like the ls command).

tin

Interactive news reader.

top

A common tool used to display information about the top processes on the system.

UDP

User Datagram Protocol. Part of TCP/IP used for control messages and data transmission where the delivery acknowledgment is not needed. The application program must ensure data transmission in this case.

UID

User ID number.

UIL

Motif User Interface Language.

URL

Uniform Resource Locator. The method of specifying the protocol, format, login (usually omitted), and location of materials on the Internet.

Usenet

See Netnews.

UUCP

UNIX-to-UNIX copy program. Used to build an early, informal network for the transmission of files, email, and Netnews.

variables, attributes

The modifiers that set the variable type. A variable can be string or integer, left- or right-justified, read-only or changeable, and other attributes.

variables, environmental

A place to store data and values (strings and integers) in the area controlled by the shell so they are available to the current and subprocesses. They can just be local to the current shell or available to a subshell (exported).

variables, substitution

The process of interpreting an environmental variable to get its value.

WAN

Wide Area Network.

Web

See World Wide Web.

whitespace

Blanks, spaces, and tabs that are normally interpreted to delineate commands and filenames unless quoted.

wildcard

Means of specifying filename(s) whereby the operating system determines some of the characters. Multiple files might match and will be available to the tool.

World Wide Web

A collection of servers and services on the Internet that run software and communicate using a common protocol (HTTP). Instead of the users’ having to remember the location of these resources, links are provided from one Web page to another through the use of URLs.

W W W

See World Wide Web.

WYSIWYG

What You See Is What You Get.

X

See X Window System.

X Window System

A windowing and graphics system developed by MIT, to be used in client/server environments.

X11

See X Window System.

X-windows

The wrong term for the X Window System. See X Window System.

yacc

Yet another compiler compiler.

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Poornima College of Engineering