NETWORK+ GUIDE TO NETWORKS, FOURTH EDITION - CHAPTER 9 docx

Objectives continued• Install and configure Linux on an Intel-based PC • Manage users, groups, and file access permissions in Solaris, Linux, and Mac OS X Server • Explain how computers

Network+ Guide to Networks,

Fourth Edition

Chapter 9 Networking with UNIX-Type

of Operating Systems

• Describe the origins and history of the UNIX

operating system

• Identify similarities and differences between

popular implementations of UNIX

• Describe the features and capabilities of servers running Solaris, Linux, and Mac OS X Server

• Explain and execute essential UNIX commands

Objectives (continued)

• Install and configure Linux on an Intel-based PC

• Manage users, groups, and file access permissions

in Solaris, Linux, and Mac OS X Server

• Explain how computers running other operating

systems can connect to UNIX servers

A Brief History of UNIX

• UNIX led to development of TCP/IP

• Numerous vendors sell different UNIX varieties

• Ken Thompson and Dennis Ritchie developed

UNIX at Bell Labs (part of AT&T)

A Brief History of UNIX (continued)

• Berkeley Software Distribution (BSD): Berkeley

versions of UNIX

– Added TCP/IP network subsystem to UNIX

• AT&T sold rights to UNIX

– Now owned by two groups:

• The SCO Group owns rights to UNIX source code

• The Open Group owns UNIX trademark

Varieties of UNIX

• All flavors of UNIX share the following features:

– Support multiple, simultaneously logged-on users

– Coordinate multiple, simultaneously running tasks

– Mount disk partitions on demand

– Apply permissions for file and directory access and modification

– Uniform method of issuing data to or receiving data from hardware devices, files, and running programs – Start programs without interfering running programs

Varieties of UNIX (continued)

• All flavors of UNIX share the following features

(continued):

– Hundreds of subsystems, including dozens of

programming languages

– Source code portability

– Window interfaces (e.g., X Windows)

• Two main categories:

– Proprietary

– Open source

Proprietary UNIX

• Source code either unavailable or available only by purchasing licensed copy from the SCO Group

– Mac OS X Server: Apple

• Runs on PowerPC-based computers – Solaris: Sun

• Runs on SPARC-based workstations and servers, Intel-based Pentium-class workstations and servers – AIX: IBM

• Runs on PowerPC-based computers

• Does not run on Macs

Proprietary UNIX (continued)

• Advantages:

– Accountability and support

– Optimization of hardware and software

– Predictability and compatibility

• Customer has no access to system’s source code

– Cannot customize

Open Source UNIX

• Open source software available to anyone, without licensing fees

• Open source UNIX flavors:

Three Flavors of UNIX

• Solaris used by Sun Microsystems on its based servers

SPARC-• Linux follows standard UNIX conventions, highly stable, and free

– Developed by Linus Torvalds in 1991

– Widely supported and used

• Mac OS X Server: Runs on Apple’s Xserve line of computers as well as Power Mac computers

• All support TCP/IP and other protocols

• Support many network topologies and physical

media

UNIX Server Hardware Requirements

• Any UNIX-type OS can act as a workstation or

server OS

• Use of GUI optional

– Command line interface

• To estimate additional hardware required:

– Server usage?

– Applications and services to be run on server?

– Number of users?

– Peak usage time periods?

– Maximum tolerable downtime?

Solaris Hardware Requirements

Table 9-1: Minimum hardware requirements for Solaris 10

Linux Hardware Requirements

Table 9-2: Minimum hardware requirements for a Linux server

Mac OS X Server Hardware

Requirements

Table 9-3: Apple hardware recommendations for Mac OS X

A Closer Look at UNIX: UNIX

Multiprocessing

• Allocate separate resources (e.g., memory space)

to each process as it is created

– Enables partitioning of processes in memory

– Prevent programs from disrupting operation of entire system

• Support symmetric multiprocessing (SMP)

– Solaris: up to 128 processors

– Linux: up to 32 processors

– Mac OS X Server: up to 2 processors

The UNIX Memory Model

• Use both physical and virtual memory efficiently

• Allocate memory area for each application

– Sharing memory between programs wherever

possible

• Increases efficiency

• Most use 32-bit addressing scheme

– Enables programs to access 4 GB of memory

• Most can run on CPUs employing 64-bit addresses

• Virtual memory: disk partition or a file

The UNIX Kernel

• Core of all UNIX-type of systems

– Loaded into memory and runs computer turned on – Coordinates access to computer’s hardware

– Can add or remove functionality by loading and

unloading kernel modules

• Files containing instructions for performing specific tasks

• Kernel origins:

– Solaris: original AT&T UNIX software

– Linux: Linus Torvalds

– Mac OS X Server (XNU): Mach

UNIX System File and Directory

Structure

• First OSs to implement hierarchical file system

– /boot directory contains kernel and other system

initialization files

– Applications and services stored in /bin and /sbin

directories

– /var directory holds variable data

– Users’ login directories typically in /home

• /Users on Mac OS X Server

UNIX System File and Directory

Structure (continued)

Figure 9-1: UNIX file system hierarchy

UNIX System File Services

• Disk File Systems:

– OS’s facility for organizing, managing, and accessing files through logical structures and software routines – Native file system type on Linux is ext3

– Solaris employs UFS

– Mac OS X Server employs HFS+ file system

– Can access FAT and NTFS partitions

UNIX System File Services

(continued)

• Network File Systems (NFSs): analogous to

Windows shares or NetWare network volumes

– Attach shared file systems (or drives) from Windows, NetWare, or other UNIX servers and share files with users on other computers

– Sun Microsystems’ NFS

– Samba: open source application that implements

Windows SMB and CIFS file system protocols

• Included with Solaris, most Linux distributions, and Mac OS X Server systems by default

– Mac OS X Server uses AFP

A UNIX Command Sampler

• Command line is primary method of interacting with UNIX-type systems

• Command interpreter (shell): program that accepts and runs typed commands

– Primary UNIX command interpreter file is /bin/sh

• Every UNIX-type system contains full

documentation of UNIX commands in manual

pages (man pages)

– Access via man command

A UNIX Command Sampler

(continued)

• Nine man page sections:

– Section 1 covers commands most typically entered – Sections 2 through 5 document programmer’s

interface to UNIX system

– Section 6 documents some amusements and games included in UNIX system

– Section 7 describes device drivers

– Section 8 covers commands used by administrators

to manage system

– Section 9 documents UNIX kernel functions

programmers use when writing device drivers

A UNIX Command Sampler

(continued)

• apropos command: find possible manual page

entries for a command

• Most commands are lowercase alphabetic

characters

• To specify an option, usually type a hyphen (-)

followed by a letter

• File globbing: equivalent to using wildcards in

Windows and DOS

• UNIX directory separator character is “/”

A UNIX Command Sampler

(continued)

Table 9-4: Commonly used UNIX commands

A UNIX Command Sampler

(continued)

Table 9-4 (continued): Commonly used UNIX commands

A UNIX Command Sampler

(continued)

Table 9-4 (continued): Commonly used UNIX commands

A UNIX Command Sampler

(continued)

• Most frequently used UNIX command is ls

• For each file, system stores all information (except filename) in a file information node (i-node)

– Beginning of disk partitions contain reserved space for all i-nodes on partition

– Contain pointers to actual file contents

• Pipe (|): combine commands

– Output of one command is input to next

– Pipeline: two or more commands connected by a

pipe

A UNIX Command Sampler

(continued)

Figure 9-3: Anatomy of ls –l output

Installing Linux: Planning a Linux

Installation

• Be prepared to answer following questions:

– What is the new server’s name?

– What is the server’s IP address?

• Also need subnet mask, IP address of server’s primary gateway, and IP address of new server’s domain name server

– What kind of video card is installed in the server?

– What is the administrative user’s password?

• Root: administrating user name – How can this information be remembered?

Installing and Configuring Fedora Core

• Installation tasks:

– Select language

– Confirm keyboard layout

– Select Server installation type

– Select disk drive partitioning options

– Choose booting options

– Configure the network interface(s)

– Configure firewall and security level options

– Set the time and time zone

– Enter the root password

Administering a UNIX-type of Server

• User names and passwords used to connect

clients to network

• Access rights for groups

– Users may be members of multiple groups

• groupadd command enables addition of new group

• useradd command enables addition of new users

• Mac OS X Server uses GUI Workgroup Manager application

Establishing Groups and Users on

Linux and Solaris

• groupadd command creates new group ID and

makes group available for use

– Assign unique ID number to each group

– Does not automatically assign access rights

• useradd command adds new user ID

– Creates user ID and assigns it to one or more

groups

– -g option specifies initial group

– -G option specifies additional groups

Establishing Groups and User

on Mac OS X Server

• Use Workgroup Manager application

• Creating new group does not assign users

• Assign unique name and numeric ID to groups

Establishing Groups and User

on Mac OS X Server (continued)

Figure 9-4: User creation in Mac OS X Server’s Workgroup

Manager

Changing File Access Permissions

• Every file and directory is owned by exactly one

user and is a member of exactly one group

• By default, when a user creates a file or directory, that user is the file or directory’s owner

Changing File Access Permissions

on Linux and Solaris

• Use chgrp command to assign a file or directory to

Changing File Access Permissions

on Mac OS X Server

• Accomplished through the GUI

• Must be logged on as system administrator

Connecting to UNIX-Type of Servers

• UNIX-type of systems and Windows can both

communicate via TCP/IP

– File systems not necessarily compatible

• Samba: one application that bridges file system

incompatibility

– Provides networking services necessary to make a UNIX-type system a fully featured Windows file- and printer-sharing server

– Communicates with Windows servers using SMB

file-sharing protocol and CIFS protocol

Connecting to UNIX-Type of Servers

(continued)

• All modern flavors of UNIX, Linux, and Mac OS X Server support data sharing using directory

services based on LDAP

– Solaris: Sun Java System Directory Server

Enterprise Edition

– Linux: OpenLDAP

– Mac OS X Server: Open Directory

• UNIX-type of systems include full complement of Internet tools

– e.g., Telnet

Connecting to UNIX-Type of Servers

(continued)

Figure 9-5: Windows Telnet session

• UNIX is a stable, flexible, and efficient NOS that

relies on TCP/IP and forms the basis of much of

the Internet

• Many varieties of UNIX-type of systems exist, and each of these belong to one of two categories:

proprietary and open source

• Characteristics of UNIX-type of systems include the ability to support multiple, simultaneous users;

hierarchical files; a uniform method for interacting with files, devices, and programs; hundreds of

subsystems and dozens of programming

languages; and source code portability

• UNIX-type of systems were among the first to

include a hierarchical file system

• UNIX-type of systems support multiple file system types

• UNIX-type of network file systems include NFS and Samba

Summary (continued)

• Consult the command’s manual (man) page by

typing man command at the shell prompt, and

pressing Enter to learn more about a command

• ls command is most frequently used command

• The useradd and groupadd commands allow you to add new users and groups

• The chgrp and chmod commands assign files to

groups and change file access permissions

Summary (continued)

• Installing the Samba application on a UNIX-type of server allows it to exchange information with

Windows servers by using Windows file system

and file access protocols

• All modern flavors of UNIX, Linux, and Mac OS X Server support data sharing using directory

services based on LDAP

• Any client that runs the TCP/IP protocol can

connect to a UNIX-type of host, such as a Linux

server, through the Telnet utility