Lecture 4:Clients & WorkstationsNetwork Design & Administration

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Overview

• What are Workstations / Client machines?• Anything that an actual user sits at!• Potentially Windows 7 Professional / Ultimate,

Vista Business / Ultimate, XP Professional, Linux and OS X.• Have to be able to communicate with Servers

and use their services – otherwise standalone.• Much more likely to cause problems because

user is directly involved.2

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New Workstations

• May already be bought with an operating system on.• Generally need to install OS if:• Home version of OS – unsatisfactory.• Not corporate standard – e.g. Vista rather than

Windows 7.• User preference – only if corporation allows• Need multiple boot.• Bought bare – will use volume licencing.• Want to ensure consistency. i.e. starting from a

known state[1].3

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What do you get?

• Microsoft – basic versions of standard tools. E.g. works, outlook express…• Linux – full set of free standard tools.• Apple – complete turnkey system.

• Microsoft expect you to buy full Office suite and use Exchange server if used within a corporate environment.

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Life and Death of a Workstation[2]

• Computer is only usable in a configured state.• Entropy occurs as workstation gets modified over time (failed

installs, malware, inappropriate software).• Need to have processes / procedures to bring back to configured

state as efficiently as possible.

New

Clean Configured Unknown

Off

BuildRebuild

Initialise

Update

Retire

Debug

Entropy

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User Expectations

• A configured machine must:• Have the corporate standard word processing

package, in the standard corporate setup (e.g. with foreign language support if required by business).• Allow use of the standard email package with no

extra user initialisation.• Have any business-specific software already

installed.• Have any corporate purchased anti-virus, anti-spam,

malware software.• Have appropriate web access.

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User Expectations

• The workstation must not:• Force the user to do anything except log on to

start working.• Allow the user to install their own choices of

packages (unless authorised).• Encourage the user to keep files locally. i.e. it

must, wherever possible, default to sending work to file servers.• It may be worthwhile to provide users with a do /

don’t list when they first get a new workstation. 7

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File System Formats

Historical (nearly)

Still used

Necessary for servers

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Hard disk geometry[4]

• Hard disks usually have a number of platters contained within them.• Each side of a platter is used and will have it’s own read/write head.• Each surface will contain a number of tracks and sectors. 9

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Magnetic Disks[4]

• Example of two sectors on a portion of a disk track

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File Allocation Table Example

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Boot Sector FS Info FAT 1 FAT 2 Data

00 00 00 00 00 00 00 00 00 … 2

00 00 00 00 00 00 00 00 00 … 3

56 A3 AA 09 7C 32 C0 0C 8A … 4

00 00 00 00 00 00 00 00 00 … 5

C3 FA 77 09 4A 32 1A BB FF FF 6

3F 33 6E 23 5D 10 19 FB 84 … 7

00 00 00 00 00 00 00 00 00 … 8

00 00 00 00 00 00 00 00 00 … 9

56 33 77 09 77 32 11 00 84 … 10

00 00 00 00 00 00 00 00 00 … 11

87 45 22 56 78 44 88 99 34 … 12

234 756 FFFF7 108910 611

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Start of file

Cluster Next Cluster Cluster size is usually between 2KB and 32KB

autoexec.batcmd.com…

Directory Table

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Installing the OS

• There are a number of ways of doing this:• Locally – by typing in parameters as prompted

during the process (media option)• Using Windows Automated Installation Kit (AIK)• Can deploy from:• Media (unattended flash drive/ISO/DVD)• Network (deploy image via a network)• Server (deploy via a server)

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Windows Systems Image Manager Architecture[3]

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SIM Interface[3]

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Integrating Linux• Easy to add Windows workstations to an Active Directory Domain!• It is not so easy to integrate other Operating Systems (e.g. Linux)

Considerations for integrating Linux:1. Authenticate against the AD server• Setup Kerberos package (install using apt-get)• Configure Kerberos with realm for domain• Configure key server and domain details

• Generate a new Kerberos ticket2. Setup SMB file access (via Samba)• Configure smb.conf with realm details

3. Configure nsswitch.conf • Add WINS, DNS and BIND information

4. Join domain.5. Still have to set up file shares etc!

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Summary

• Many different methods of installation.• Can depend on starting point (e.g. upgrade or

bare machine)• More automation has more pre-requisites.• Increased automation reduces Total Cost of

Ownership (TCO)• This is critical in a business environment.

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Next Time & References• Corporate architecture• Domains and Active Directory Domain Services

[1] “The Practice of System and Network Administration”, Limoncelli, Chapter 3.1.1.4[2] “The Practice of System and Network Administration”, Limoncelli, p42, Figure 3.1 (from Evard, 1997)[3] Windows SIM architecture, Microsoft help file (WAIK) (http://technet.microsoft.com/en-us/library/cc766157%28WS.10%29.aspx)

[4] “Structured Computer Organisation”, Andrew Tanenbaum, 2006

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