Red Hat Linux Networking , System Administration (P3) potx

Standard Installation IN THIS CHAPTER ■■ Exploring Your PC’s Components ■■ Checking for Supported Hardware ■■ Creating the Red Hat Boot Disk ■■ Starting the Installation ■■ Partitioning

does not occur automatically The goal of disaster recovery is to restore fullfunctionality as quickly as possible Depending on the degree of fault toler-ance your systems have, disaster recovery may not be necessary at all.

Planning for fault tolerance and disaster recovery requires that you assessthe needs of your systems The following two questions are the most impor-tant ones you should ask:

■■ How critical are the systems to daily operation?

■■ Could the systems be down and not affect operations?

Obviously, if your systems are used for business, they could not be down forlong, if at all You must determine how vital a given system is to your opera-tion Vital systems require greater fault tolerance than nonvital systems do Besure to keep in mind that greater fault tolerance costs more than less fault tol-erance does Another important consideration is the amount of money avail-able for building fault tolerance into your system Balance your need for faulttolerance with the amount of money you can spend on it

Clustering Solutions

If your systems must be up 24/7, you have to rely on a clustering solution foryour fault tolerance You basically have two choices for clustering: failoverclustering and true clustering Both of these solutions are costly to implementand require a great deal of configuration Configuring these types of systems

is well beyond the scope of this book, but a brief description of the two types

dedi-True clustering uses multiple systems, usually more than two, often in ferent locations, that act as a single system Network services run on each sys-tem and requests for services are distributed between the systems Eachsystem is connected to every other system by a dedicated link Unlike the sec-ond system in failover clustering that only listens for the heartbeat, the sys-tems in true clustering handle requests for services If a system does go down,the requests for service are just sent to the other systems, which take up theslack Neither clustering solution employs disaster recovery Because they

dif-must be up 100 percent of the time, there is no disaster from which to recover,except perhaps the disaster to your budget because the cost of implementingsuch a system is quite high.

Disaster Recovery

For systems that do not require 100 percent uptime, disaster recovery is themethod used A typical solution is to configure an identical system and keep itready for service Placing the other system into service requires intervention

by the administrator and no services will be possible during this time Servicecan usually be restored fairly quickly using this method, and the cost is lessthan the cost of a clustering solution

The least costly method (in hardware) of dealing with system problems is tofix them after they have occurred Here, you shut down the system until it isfixed; no services are available during the repair For example, if the hard drive

in your system crashes, you simply replace the hard drive

System administrators who plan their network well may not be able to vent disasters entirely, but they greatly reduce the likelihood of such eventstaking place and make complete or near-complete recovery a quick andorderly process

pre-Planning for recovery ideally involves considering everything bad that canpossibly happen and figuring out a way around it However, that which is idealoften does not square with what’s practical, especially when it involves spend-ing money to guard against an infinitesimal likelihood Fortunately, the thingsthat save you from likely disasters save you from the most unlikely ones, too

Just as security planning requires attention to threats from outside andinside the network, there are two parts to disaster planning The first is doingeverything you can to prevent a catastrophe from taking place

Only you, or other administrators at your organization, know how tant your system is and how much money is budgeted to keep it running.Chances are good that an uninterruptible power supply (UPS) that keeps thenetwork up long enough to save and close files and shut down the system in

impor-an orderly fashion fits within the available budget A good UPS system is cially useful if your enterprise has a generator backup that kicks on in theevent of power failure because generators do not always start instantly and,when they do, the electricity provided is not always clean enough for com-puter use A battery backup can protect you from both of these potential prob-lems If your enterprise is important enough to have an emergency generator,it’s probably important enough to keep the network running

espe-Renegade electricity is one of the worst enemies of system reliability Smallpower strips with surge suppression are better than nothing, but more robustpower conditioning is needed if really important equipment and data are to beprotected In fact, be sure to protect all lines from the outside world that attach

to your computer or its peripherals, be they phone lines or cable or DSL nections Likewise, put the peripherals themselves on protected circuits.Second, formulate a regular (daily or better) backup scheme, with one set ofbackups stored in a safe place off-site as protection against loss of data in theevent of fire, flood, tornado, or other physical disaster One way of making thisprocess relatively painless, albeit an expensive one, is to rent storage from acommercial operation whose business is storing other people’s data The bestfirms are very responsive and secure

con-Redundancy is also important Make sure that your plans don’t put criticaldata on only one machine That way, in the event of a machine failure, areplacement machine with a copy of your critical data can be put online veryquickly This is some, but not all, of the theory behind redundant array of inde-pendent disks (RAID) systems, in which multiple hard drives in the samemachine contain the same data RAID is good protection in case any one drivefails (The best RAIDs allow the hot-swapping of drives so that a replacementcan be added without bringing the system down.) But RAID also allows formuch faster data access, making it especially useful for file server machines.Don’t be lulled into complacency by a RAID, though; there are computer fail-ure modes that can render an entire system useless In keeping with Murphy’sLaw, the worst failures and calamities occur at the worst possible time — justbefore the rollout of a new product, just as the monthly billing is scheduled to

go out, in the middle of the worst blizzard in 10 years, or when most of thecomputer staff is on vacation or out sick You need to establish an emergencyresponse policy that takes these examples, and there are many others, intoaccount This involves convincing your employer of the necessity of havingsufficient staff to guard against such horrors, or even the employment of anoutside firm to augment your own staff in the event of an especially ill-timeddisaster If your company follows the latter route, it’s well worth the invest-ment of time and money to make sure that the outside firm’s representativestour and learn your network on a day when everything is working smoothly.Some of this planning is far more elaborate than anything you’re likely toundertake if you have only a small household network or a very small office; onthe other hand, if you’re in a very large enterprise, data security and systemintegrity involve issues and procedures far beyond the scope of this book.Everything mentioned in this section, however, can be scaled to fit any network

Writing It Down: Good Records Can Save Your Job

A very important part of network planning is to put it all down on paper and

to save that piece of paper Working out your network’s design is best done byactually diagramming the network, making multiple diagrams to explore dif-ferent strategies Once you settle on a design, draw a more formal diagram

Sometimes it’s a good idea to save your discarded designs as well, with a note

on each version explaining why it wasn’t chosen Formalizing the networkdesign and saving the discarded ideas is useful for several reasons It bolstersyour decisions in case you’re second-guessed, it demonstrates that you con-sidered all the possibilities, and the formal diagram is a valuable tool shouldsomeone need to administer the system in your absence

A written security policy is essential in the enterprise and not a bad ideaeven for a home network An additional security file you should always keep

is a full security log Such a record might begin by detailing what security sures you have designed into the system It should include copies of any secu-rity notices you have received, as well as an initialed notation of when therecommended security patch was applied If log files show an attempted crack

mea-of your network, hard copies mea-of the relevant portions should be kept there, too When users or management complain about how you have the system sotight that it seems inconvenient even for them to log in, there’s nothing likeproving that the system is regularly under attack — and it will be, by portscanners and others — to demonstrate the wisdom of tight security One verybig company has made huge amounts of money by putting user convenienceover security, and many companies have paid a high price for adopting theirproducts Your Red Hat system costs a very small amount in user inconve-nience in exchange for greatly enhanced system security It’s useful to be able

to prove that the threat is real

A security log is also the place to keep copies of any security-related emailmessages from within the company, from log listings of employees who havedecided to “go exploring” (which is sometimes but not always a sign of badintent) to exchanges with management over the implementation of new secu-rity features This file is not something for general consumption, but it’s veryimportant Keep a copy locked away at work, and it won’t hurt to keep a copysafely off-site, too

C R O S S - R E F E R E N C E To learn more about writing a security policy, see Chapter 34.

While your security log should detail actions you have taken to prevent aster and actions you have recommended in that regard, your plan of action inthe event of a catastrophe should also be committed to paper and should bewell known and easily available If you are the sole administrator, it is far bet-ter to work out your plan of action calmly and ahead of time, which of courseyou will have done But under the stress of an actual emergency, it is easy toforget important details Having a specific plan on paper right in front of you

dis-is a big help and a great stress reliever Your action plan should be sufficientlydetailed so that if the disaster takes place while you are away, any competent

system administrator can use it to bring the system back up If you are part of

a larger department, include the assignments of others in restoring the system

In either case, someone who is completely trusted and who is never on tion at the same time you are should know the root’s password Alternately,the password can be placed in a sealed envelope inside the company safe —the one time it is allowable to put a password on paper

vaca-T I P Keep a hard copy of your security log in a safe place!

We’re all happy with the idea of the paperless office, but until computersbecome perfectly reliable, paper — as a roadmap, indicating where you areand how you arrived there — will remain necessary

Summary

In this chapter you learned the importance of planning your network beforeyou begin to construct it, discovered some of the options available to you, andfound out some of the reasons why you might choose one over another Youlearned that network security is a never-ending task made easier by carefulplanning and that threats can come both from outside the network and fromamong its users Working to prevent catastrophic failures and having a plan torecover from them is something you’ve learned to do You now know theimportance of putting it all on paper as you proceed, too

Standard Installation

IN THIS CHAPTER

■■ Exploring Your PC’s Components

■■ Checking for Supported Hardware

■■ Creating the Red Hat Boot Disk

■■ Starting the Installation

■■ Partitioning the Hard Disk

■■ Using Disk Druid to Partition Your Disks

■■ Configuring the Installation

■■ Selecting the Package Groups to Install

■■ Running Firstboot

This chapter explains the steps necessary to install Red Hat Enterprise Linux andFedora Core on a single system You begin by making a list of your PC’s hard-ware You use this hardware inventory later when you begin the installation

N OT E When you purchase Red Hat Enterprise Linux, you are eligible for installation support from Red Hat Also, an online installation manual is available on the Red Hat Web site at www.redhat.com/docs There is no official support for Fedora Core from Red Hat.

N OT E The installation processes for Red Hat Enterprise Linux and Fedora Core are nearly identical Throughout the remainder of this chapter, we will refer to both Red Hat Enterprise Linux and Fedora Core as Red Hat Linux except

in the instances where it is necessary to make a distinction between them The figures in the chapter show the Fedora installation screens, but with the exception of the name on the screen (Fedora or Enterprise Linux), the content

of the installation screens is identical.

C H A P T E R

3

Exploring Your PC’s Components

Before installing Red Hat Linux, you should compile a list of the hardwarecomponents in your computer Linux supports different types of hardware

through software components called device drivers, similarly to other operating

systems A driver is required for each type of peripheral device; depending onthe age of your hardware, a driver may not be available If your hardware iscurrent, meaning less than two years old, the drivers you need are probablyavailable and included with the distribution If you need a driver that is notincluded with the distribution, searching the Internet usually provides youwith a solution

You can install and run Red Hat Linux even if no Linux drivers are availablefor certain devices Of course, those devices won’t function, but this may not

be a problem for you, depending on the device To be able to install Red HatLinux, you must have a compatible processor, bus type, floppy disk, hard disk,video card, monitor, keyboard, mouse, and CD-ROM drive If you are plan-ning to use a graphical user interface (GUI), such as GNOME or KDE, youmust ensure that XFree86 (the X Window System for Linux) supports themouse, video card, and monitor Nearly all devices made within the past twoyears are supported

The following sections briefly describe the supported PC hardware Yourhardware list should contain information about the hardware described herebefore you begin to install Red Hat Linux on your PC

Processor

The central processing unit (CPU) — or just the processor — is an integrated

cir-cuit chip that performs nearly all control and processing functions in the PC.Both Red Hat Enterprise Linux and Fedora Core run on an Intel 80386 proces-sor or newer, as well as compatibles made by AMD or Cyrix However, youprobably don’t want to use any processor older than a Pentium-class proces-sor Red Hat Linux also supports motherboards with multiple processors that

use the symmetric multiprocessing (SMP) Linux kernel.

Bus

The bus provides the electrical connection between the processor and its

periph-erals Several types of PC buses exist on the motherboard with slots to acceptperipheral components Each of the slots is colored to help in its identification

The most recent is the Peripheral Component Interconnect (PCI) bus, and it is found

on all current production motherboards The PCI slot is white and is available

in 32- and 64-bit form as well as 33 and 64 MHz The new PCI-X standard will

support speeds up to 533 MHz Another type of slot is also based on the PCI bus

specifications, but offers significant advantages over the PCI bus The Accelerated

Graphics Port (AGP) is a special slot on the motherboard designed to accept an

AGP graphics card The AGP slot is brown Another is the Industry Standard

Architecture (ISA) bus, formerly called the AT bus because IBM introduced it in

the IBM PC-AT computer in 1984 The ISA bus is black Other, less frequently

encountered, buses because of their aging status include Extended Industry

Stan-dard Architecture (EISA); VESA local (VL-bus); and Micro Channel Architecture (MCA) Red Hat Enterprise Linux supports all of these buses.

Memory

Referred to as random access memory, or RAM, is not a consideration in

deter-mining compatibility This means that Linux does not care what kind of ory it is or how fast it is, it just uses whatever is there For good performancethough, you need at least 64 MB of RAM for a text install and 192 MB for agraphical install If you are planning to run the X Window system to use agraphical user interface (GUI) on the PC, you need even more memorybecause the X Window System manages the graphical interface through an Xserver, which is a large program that needs a lot of memory to run efficiently.Red Hat recommends a minimum of 256 MB RAM to run a graphical system

mem-T I P If you are buying a new PC, it probably comes with 128 MB or more RAM.

If you can afford it, buy as much RAM as you can The more RAM a system has, the more efficiently it runs multiple programs (because the programs can all fit

in memory) Red Hat Linux can use a part of the hard disk as virtual memory.

Such disk-based memory, called swap space, is much slower than physical

memory.

Video Card and Monitor

If you are not planning to use the X Window system, any video card works.Red Hat Linux supports all video cards in text mode If you are planning to usethe X Window system, be sure to find a video card that is supported by

XFree86, which is the version of the X Window System used in Red Hat Linux.

It is pretty unlikely that you would find a video card that doesn’t work with X,but you can save yourself a lot of aggravation if your video card is supported

by XFree86

Your choice of monitors depends on your use of the X Window system Fortext mode displays, typically used on servers, any monitor will do If you aresetting up a workstation, or using the X Window system on your server, choose

a monitor that supports the display resolution you use Resolution is expressed

in terms of the number of picture elements, or pixels, horizontally and vertically

(such as 1024 ×768)

XFree86’s support for a video card depends on the video chipset — the

inte-grated circuit that controls the monitor and causes the monitor to display put You can find out the name of the video chipset used in a video card fromthe card’s documentation

out-Your video card’s name may not be in the list at the Red Hat site The tant thing to note is the name of the video chipset Many popular video cardsmade by different manufacturers use the same video chipsets Look for thename of the video chipsets listed at the Red Hat site In nearly all cases, the RedHat installation program automatically detects the video chipset as it sets upthe X Window System

impor-Hard Drive

Red Hat Linux supports any IDE hard drive that your PC’s basic input/output

system (BIOS) supports, as long as the system BIOS supports the hard drive

without any additional drivers This would include EIDE- and ATA-compatibledrives as well

For hard drives connected to your PC through a Small Computer SystemInterface (SCSI) controller card, Red Hat Linux must have a driver that enablesthe SCSI controller to access and use the hard drive If you have a recent SCSIcontroller card, there is most likely a driver for it already included with the dis-tribution

Also supported are Serial Advanced Technology Attachment (SATA) drives,which use serial technology instead of the parallel ATA technology currentlyused by IDE drives SATA provides a significant speed increase over IDE

As for the size (storage capacity) of the drive, most new systems seem tohave drives 20 GB or larger You should buy the highest capacity drive you canafford

Floppy Disk Drive

Linux drivers use the PC BIOS to access the floppy disk drive, so any floppydisk drive is compatible with Red Hat Linux The Red Hat installation programcan be started from the CD-ROM if your PC has one and is able to boot from it

If not, you have to boot Red Hat Linux from a floppy disk drive during theinstallation, so you need a high-density 3.5-inch (1.44-MB capacity) floppy diskdrive You can also avoid booting from a floppy if you can boot your PC underMS-DOS (not an MS-DOS window under Windows 95/98/2000), and you canaccess the CD-ROM from the DOS command prompt

Keyboard and Mouse

Red Hat Linux supports any keyboard that already works with your PC Themouse, however, needs explicit support in Red Hat Linux You need a mouse ifyou want to configure and run XFree86, the X Window System for Linux RedHat Linux supports most popular mice, including the commonly found PS/2and USB mouse Red Hat Linux also supports touch pad devices, such as ALPSGlidePoint, as long as they are compatible with one of the supported mice

SCSI Controller

The Small Computer System Interface, commonly called SCSI (and pronounced

“skuzzy”), is a standard way of connecting many types of peripheral devices to

a computer SCSI is used in many kinds of computers, from servers to high-endUNIX workstations to PCs Typically, you connect hard drives and CD-ROMdrives through a SCSI controller To use a SCSI device on your PC, you need

a SCSI controller card that plugs into one of the bus connector slots on yourPC’s bus

If you want to access and use a SCSI device under Linux, you have to makesure that Red Hat Linux supports your SCSI controller card

CD/DVD-R/RW Drive

CD-R (compact disc read-only) drives are popular because each CD-ROM can

hold up to 650 MB of data, a relatively large amount of storage compared with

a floppy disk CD-ROMs are reliable and inexpensive to manufacture Vendorscan use a CD-ROM to distribute a large amount of information at a reasonablecost

ROM drives are found already installed on many new systems ROM discs are capable of storing up to 4.7 GB and are most frequently used torecord digital video, but can be used to hold any data

DVD-CD-RW and DVD-R/RW and DVD+R/RW drives are used to create CDsand DVDs, respectively Either of these types of drives can be used in your RedHat system Any IDE/ATAPI-compatible drive, as well as SCSI drives, willwork with Red Hat Enterprise Linux

Sound Card

If you are configuring a server, you probably aren’t too interested in playingsounds But with Red Hat Linux you can play sound on a sound card to enjoymultimedia programs and games If you have a sound card, you can also playaudio CDs Nearly all sound cards available today, whether built into themotherboard or a separate card that plugs into a bus socket, are supported

Network Card

A network interface card (NIC) is necessary if you connect your Red Hat Linux

PC to a local area network (LAN), which is usually an Ethernet network If you

are configuring a server, you certainly want to configure at least one networkcard Red Hat Enterprise Linux supports a variety of Ethernet network cards.ARCnet and IBM’s Token Ring network are also supported Check the hard-ware list on the Red Hat site to see if your NIC is supported Nearly all NICscurrently in use are supported

For any Red Hat Linux PC connected to a network, you need the followinginformation:

■■ Hostname of the PC

■■ Domain name of the network

■■ Internet Protocol (IP) address of the PC

■■ Address of the gateway

■■ IP address of name servers

N OT E If you plan to use DHCP to obtain your IP information, you do not need

to specify the IP information in the above list.

Checking for Supported Hardware

To check if Red Hat Linux supports the hardware in your PC, follow thesesteps:

1 Make a list of the make, model, and other technical details of all ware installed in your PC Most of this information is in the manualsthat came with your hardware If you don’t have the manuals, and youalready have an operating system (MS Windows for example) on the

hard-PC, you may be able to obtain this information from that operating tem Refer to that operating system’s instructions for obtaining hard-ware information

sys-2 Go to the Red Hat Web site at redhat.com/hardware Compare yourhardware list to the list of hardware that the latest version of Red HatLinux supports If the components listed earlier are supported, you canprepare to install Red Hat

N OT E You do not need a boot disk if you can start your PC from your CD-ROM drive The first installation disk is a bootable CD-ROM and can be used to start the installation process If you can boot from your CD-ROM, skip to the “Starting the Red Hat Linux Installation” section If you are unable to boot from your CD-ROM drive, continue to the next section, “Creating the Red Hat Boot Disk,”

and then go to the installation section.

Creating the Red Hat Boot Disk

To boot Red Hat Linux for the first time and start the Red Hat Linux tion program, you need a Red Hat boot disk For this step, you should turn onyour PC without any disk in the A drive and run Windows as usual

installa-N OT E You do not need a boot disk if you can start your PC under MS-DOS (not an MS-DOS window in Windows) and access the CD-ROM from the DOS command prompt If you run Windows, restart the PC in MS-DOS mode.

However, you may not be able to access the CD-ROM in MS-DOS mode because the startup files (AUTOEXEC.BAT and CONFIG.SYS) may not be configured correctly To access the CD-ROM from DOS, you typically must add a CD-ROM driver in CONFIG.SYS and add a line in AUTOEXEC.BAT that runs the MSCDEX program Try restarting your PC in MS-DOS mode and see whether the CD-ROM can be accessed.

The Red Hat boot disk starts your PC and the Red Hat Linux installationprogram After you install Red Hat Linux, you no longer need the Red Hatboot disk (except when you want to reinstall Red Hat Linux from theCD-ROMs)

The Red Hat boot disk contains an initial version of the Red Hat Linuxinstallation program that you use to start Red Hat Enterprise Linux, preparethe hard disk, and load the rest of the installation program Creating the RedHat boot disk involves using a utility program called RAWRITE.EXE to copy aspecial file called the Red Hat Linux boot image to a disk

To create the Red Hat boot disk under Windows, follow these steps:

1 In Windows 95/98/ME open an MS-DOS window (select Start ➪ grams ➪ MS-DOS Prompt) In Windows 2000 or XP, select Start ➪ Run

Pro-and enter cmd in the dialog box.

2 In the MS-DOS window, enter the following commands at the MS-DOSprompt (Our comments are in parentheses and your input is in

boldface.)

a d: (use the drive letter for the CD-ROM drive)

b cd \dosutils

c rawrite

d Enter disk image source filename: \images\boot.img

e Enter target disk drive: a

f Insert a formatted disk into drive A and press ENTER.

3 As instructed, you should put a formatted disk into your PC’s A driveand press Enter RAWRITE.EXE copies the boot-image file to the disk.When the DOS prompt returns, remove the Red Hat boot disk from the floppydrive and label it as a Red Hat boot disk

Starting the Installation

To start the Red Hat Linux installation, power up the PC and put the Red HatInstallation CD-ROM 1 (and the boot disk if you created one) into your PC’sCD-ROM drive (and floppy drive if applicable) The PC boots Red Hat Linuxand begins running the Red Hat installation program The Red Hat installationprogram controls the installation of the operating system

N OT E If you are using a boot disk that you created, be sure to place the first installation CD-ROM in the CD-ROM drive after you start the PC The installation program looks for the Red Hat Linux CD-ROMs to start the installation in graphical mode If the installation program can’t find the CD-ROM, the installation program starts in text mode and prompts for it.

A few moments after you start the boot process, an initial screen appears.The screen displays a welcome message and ends with a boot: prompt Thewelcome message tells you that more information is available by pressing one

of the function keys F1 through F5

If you want to read the help screens, press the function key corresponding tothe help you want If you don’t press any keys after a short delay, the bootprocess proceeds with the loading of the Linux kernel into the PC’s memory

To start booting Red Hat Linux immediately, press Enter

N OT E On CDs that you made from downloaded ISO files (Fedora Core) you are prompted to check the CD media for errors The disk-checking process takes

a few minutes but is time well spent to be sure there are no errors on your installation CDs To begin disk checking, press Enter You will be prompted to change the disks as required You can also choose to skip disk checking by using the Tab key to highlight Skip and then pressing Enter If you purchased Red Hat Enterprise Linux, you are not prompted to check the disks.

After the Linux kernel loads, it automatically starts the Red Hat Linuxinstallation program This, in turn, starts the X Window System, which pro-vides a graphical user interface for the installation

You should compile all the configuration information explained earlier inthis chapter before you begin If the installation program detects your hard-ware, installing Red Hat Linux from the CD-ROM on a 200-MHz or better Pen-tium PC should take 30 to 40 minutes

N OT E During installation, the Red Hat installation program tries to determine the hardware in your PC and alters the installation steps as required For example, if the installation program detects a network card, the program displays the appropriate network configuration screens If a network card is not detected, the network configuration screens are not displayed So, depending

on your specific hardware, the screens you see during installation may differ from those shown in this section.

C R O S S - R E F E R E N C E If you run into any problems during the installation, refer to Chapter 35 to learn how to troubleshoot common installation

2 After clicking Next, a list of languages to use during the installation isdisplayed, as shown in Figure 3-1 Use your mouse to select the lan-guage you want to use for installation, and then click the Next button

to proceed to the next step

Figure 3-1 Choosing the installation language.

N OT E In the graphical installation, each screen has online help available on the left side of the screen You can read the help message to learn more about what you are supposed to select in a specific screen.