Tải bản đầy đủ - 0 (trang)
X. Thou Shalt Write Down Thy Network Configuration upon Tablets of Stone

X. Thou Shalt Write Down Thy Network Configuration upon Tablets of Stone

Tải bản đầy đủ - 0trang

Chapter 28



Ten Big Network Mistakes



J



ust about the time you figure out how to avoid the most embarrassing

computer mistakes (such as using your CD drive’s tray as a cup holder),

the network lands on your computer. Now you have a whole new list of dumb

things you can do, mistakes that can give your average computer geek a belly

laugh because they seem so basic to him. Well, that’s because he’s a computer

geek. Nobody had to tell him not to fold the floppy disk — he was born with

an extra gene that gave him an instinctive knowledge of such things.

Here’s a list of some of the most common mistakes made by network novices.

Avoid these mistakes and you deprive your local computer geek of the pleasure

of a good laugh at your expense.



Skimping on Cable

If your network consists of more than a few computers or has computers

located in different rooms, invest in a professional-quality cable installation,

complete with wall-mounted jacks, patch panels, and high-quality network

switches. It’s tempting to cut costs by using cheap switches and by stringing

inexpensive cable directly from the switches to each computer on the network. In the long run, though, the Scrooge approach may actually prove to be

more expensive than investing in a good cable installation in the first place.

Here are just a few of the reasons it pays to do the cabling right in the first place:



A good cable installation lasts much longer than the computers it services.

A good cable installation can last 10 or 15 years, long after the computers

on your network have been placed on display in a computer history

museum.



Installing cable is hard work. No one enjoys going up in the attic, poking

his head up through ceiling panels and wiping fiberglass insulation out

of his or her hair, or fishing cables through walls. If you’re going to do it,

do it right so you don’t have to do it again in just a few years. Build your

cable installation to last.



Your network users may be satisfied with 100 Mbps networking now, but

it won’t be long before they demand gigahertz speed. And who knows

how fast the next wave of networking will be? If you cut costs by using



www.it-ebooks.info



406



Part VII: The Part of Tens

plain Cat5 cable instead of more expensive Cat6 cable, you’ll have to

replace it later.



You might be tempted to skip the modular wall jacks and patch cables

and instead just run the cable down the wall, out through a hole, and then

directly to the computer or hub. That’s a bad idea because the connectors are the point at which cables are most likely to fail. If a connector fails,

you have to replace the entire cable — all the way up the wall, through the

ceiling, and back to the switch. By wiring in a wall-jack and using a patch

cable, you have to replace only the patch cable when a connector fails.

For more information about professional touches for installing cable, see

Chapter 5.



Turning Off or Restarting a Server

Computer While Users Are Logged On

The fastest way to blow your network users’ accounts to kingdom come is to

turn off a server computer while users are logged on. Restarting it by pressing its reset button can have the same disastrous effect.

If your network is set up with a dedicated file server, you probably won’t be

tempted to turn it off or restart it. But if your network is set up as a true peerto-peer network, where each of the workstation computers — including your

own — also doubles as a server computer, be careful about the impulsive

urge to turn off or restart your computer. Someone may be accessing a file or

printer on your computer at that very moment.

So, before you turn off or restart a server computer, find out whether anyone

is logged on. If so, politely ask her to log off.

Many server problems don’t require a server reboot. Instead, you can often

correct the problem just by restarting the particular service that’s affected.



Deleting Important Files on the Server

Without a network, you can do anything you want to your computer, and the

only person you can hurt is yourself. (Kind of like the old “victimless crime”

debate.) Put your computer on a network, though, and you take on a certain

amount of responsibility. You must find out how to live like a responsible

member of the network society.

Therefore, you can’t capriciously delete files from a network server just

because you don’t need them. They may not be yours. You wouldn’t want

someone deleting your files, would you?



www.it-ebooks.info



Chapter 28: Ten Big Network Mistakes

Be especially careful about files that are required to keep the network running.

For example, some versions of Windows use a folder named wgpo0000 to hold

e-mail. If you delete this folder, your e-mail is history. Look before you delete.

The first time you accidentally delete an important file from a network share,

you may be unpleasantly surprised to discover that the Recycle Bin does not

work for network files. The Recycle Bin saves copies of files you’ve deleted from

your computer’s local hard disk, but it does not save copies of files you delete

from network shares. As a result, you can’t undelete a file you’ve accidentally

deleted from the network.



Copying a File from the Server, Changing

It, and Then Copying It Back

Sometimes working on a network file is easier if you first copy the file to your

local hard drive. Then you can access it from your application program more

efficiently because you don’t have to use the network. This is especially true

for large database files that have to be sorted to print reports.

You’re asking for trouble, though, if you copy the file to your PC’s local hard

drive, make changes to the file, and then copy the updated version of the file

back to the server. Why? Because somebody else may be trying the same

thing at the same time. If that happens, the updates made by one of you —

whoever copies the file back to the server first — are lost.

Copying a file to a local drive is rarely a good idea.



Sending Something to the Printer Again

Just Because It Didn’t Print the First Time

What do you do if you send something to the printer and nothing happens?



Right answer: Find out why nothing happened and fix it.



Wrong answer: Send it again and see whether it works this time.

Some users keep sending it over and over again, hoping that one of

these days, it’ll take. The result is rather embarrassing when someone

finally clears the paper jam and then watches 30 copies of the same

letter print. Or when 30 copies of your document print on a different

printer because you had the wrong printer selected.



www.it-ebooks.info



407



408



Part VII: The Part of Tens



Assuming That the Server

Is Safely Backed Up

Some users make the unfortunate assumption that the network somehow

represents an efficient and organized bureaucracy worthy of their trust. This

is far from the truth. Never assume that the network jocks are doing their

jobs backing up the network data every day, even if they are. Check up on

them. Conduct a surprise inspection one day: Burst into the computer room

wearing white gloves and demand to see the backup tapes. Check the tape

rotation to make sure that more than one day’s worth of backups is available.

If you’re not impressed with your network’s backup procedures, take it upon

yourself to make sure that you never lose any of your data. Back up your

most valued files to a flash drive.



Connecting to the Internet without

Considering Security Issues

If you connect a non-networked computer to the Internet and then pick up

a virus or get yourself hacked into, only that one computer is affected. But

if you connect a networked computer to the Internet, the entire network

becomes vulnerable.

Beware: Never connect a networked computer to the Internet without first

considering the security issues:



How will you protect yourself and the network from viruses?



How will you ensure that the sensitive files located on your file server

don’t suddenly become accessible to the entire world?



How can you prevent evil hackers from sneaking into your network,

stealing your customer file, and selling your customer’s credit card data

on the black market?





For answers to these and other Internet-security questions, see Chapter 23.



www.it-ebooks.info



Chapter 28: Ten Big Network Mistakes



Plugging In a Wireless Access

Point without Asking

For that matter, plugging any device into your network without first getting

permission from the network administrator is a big no-no. But wireless access

points (WAPs) are particularly insidious. Many users fall for the marketing

line that wireless networking is as easy as plugging in one of these devices

to the network. Then, your wireless notebook PC or handheld device can

instantly join the network.

The trouble is, so can anyone else within about one-quarter mile of the WAP.

Therefore, you must employ extra security measures to make sure hackers

can’t get into your network via a wireless computer located in the parking lot

or across the street.

If you think that’s unlikely, think again. Several underground Web sites on the

Internet actually display maps of unsecured wireless networks in major cities.

For more information about securing a wireless network, see Chapter 9.



Thinking You Can’t Work Just

Because the Network Is Down

A few years back, I realized that I can’t do my job without electricity. Should

a power failure occur and I find myself without electricity, I can’t even light a

candle and work with pencil and paper because the only pencil sharpener I

have is electric.

Some people have the same attitude about the network: They figure that if the

network goes down, they may as well go home. That’s not always the case. Just

because your computer is attached to a network doesn’t mean that it won’t

work when the network is down. True — if the wind flies out of the network

sails, you can’t access any network devices. You can’t get files from network

drives, and you can’t print on network printers. But you can still use your computer for local work — accessing files and programs on your local hard drive

and printing on your local printer (if you’re lucky enough to have one).



www.it-ebooks.info



409



410



Part VII: The Part of Tens



Running Out of Space on a Server

One of the most disastrous mistakes to make on a network server is to let it

run out of disk space. When you buy a new server with hundreds of gigabytes

of disk space, you might think you’ll never run out of space. It’s amazing how

quickly an entire network full of users can run through a few hundred gigabytes of disk space, though.

Unfortunately, bad things begin to happen when you get down to a few gigabytes of free space on a server. Windows begins to perform poorly and may

even slow to a crawl. Errors start popping up. And, when you finally run out

of space completely, users line up at your door demanding an immediate fix:



The best way to avoid this unhappy situation is to monitor the free disk

space on your servers on a daily basis. It’s also a good idea to keep track

of free disk space on a weekly basis so you can look for project trends.

For example, if your file server has 100GB of free space and your users

chew up about 5GB of space per week, you know you’ll most likely run

out of disk space in 20 weeks. With that knowledge in hand, you can

formulate a plan.



Adding additional disk storage to your servers isn’t always the best solution to the problem of running out of disk space. Before you buy more

disks, you should





•Look for old and unnecessary files that can be removed.







•Consider using disk quotas to limit the amount of network disk

space your users can consume.



Always Blaming the Network

Some people treat the network kind of like the village idiot who can be

blamed whenever anything goes wrong. Networks cause problems of their

own, but they aren’t the root of all evil:



If your monitor displays only capital letters, it’s probably because you

pressed the Caps Lock key.

Don’t blame the network.



If you spill coffee on the keyboard, well, that’s your fault.

Don’t blame the network.



If your toddler sticks Play-Doh in the floppy drive, kids will be kids.

Don’t blame the network.

Get the point?



www.it-ebooks.info



Chapter 29



Ten Things You Should

Keep in Your Closet



W



hen you first network your office computers, you need to find a closet

where you can stash some network goodies. If you can’t find a whole

closet, shoot for a shelf, a drawer, or at least a sturdy cardboard box.

Here’s a list of what stuff to keep on hand.



Duct Tape

Duct tape helped get the crew of Apollo 13 back from their near-disastrous

moon voyage. You won’t actually use it much to maintain your network,

but it serves the symbolic purpose of demonstrating that you realize things

sometimes go wrong and you’re willing to improvise to get your network up

and running.

If you don’t like duct tape, a little baling wire and some chewing gum serve

the same symbolic purpose.



Tools

Make sure that you have at least a basic computer toolkit, the kind you can

pick up for $15 from just about any office supply store. At the minimum,

you’ll need a good set of screwdrivers, plus wire cutters, wire strippers, and

cable crimpers for assembling RJ-45 connectors.



www.it-ebooks.info



412



Part VII: The Part of Tens



Patch Cables

Keep a good supply of patch cables on hand. You’ll use them often: when

you move users around from one office to another, when you add computers

to your network, or when you need to rearrange things at the patch panels

(assuming you wired your network using patch panels).

When you buy patch cables, buy them in a variety of lengths and colors. One

good way to quickly make a mess of your patch panels is to use 15' cables

when 3' cables will do the job. And having a variety of colors can help you

sort out a mass of cables.





The last place you should buy patch cables is from one of those big-box office

supply or consumer electronics stores. Instead, get them online. Cables that

sell for $15 or $20 each at chain stores can be purchased online for $3 or $4

each.



Cable Ties

Cable ties — those little plastic zip things that you wrap around a group of

cables and pull to tighten — can go a long way toward helping keep your network cables neat and organized. You can buy them in bags of 1,000 at big-box

home-improvement stores.



Twinkies

If left sealed in their little individually wrapped packages, Twinkies keep for

years. In fact, they’ll probably outlast the network itself. You can bequeath

them to future network geeks, ensuring continued network support for generations to come.

In November of 2012, computer geeks throughout the world faced a crisis

far more menacing than the end of the Mayan calendar: the possible end of

Hostess and Twinkies. Fortunately, the gods intervened, and Twinkies were

saved, thus ensuring the continued operation of computer networks throughout the globe.



www.it-ebooks.info



Chapter 29: Ten Things You Should Keep in Your Closet



Extra Network Cards

Ideally, nearly all your computers will have network interfaces built directly into

the motherboard. However, you will occasionally find that the motherboard’s

network interface goes bad. Rather than replace the entire motherboard, you

can often fix the problem by adding a cheap (less than $20) network card to

use instead of the on-board network interface.



Cheap Network Switches

Keep a couple of inexpensive (about $20) four- or eight-port network switches

on hand. You don’t want to use them for your main network infrastructure, but

they sure come in handy when you need to add a computer or printer somewhere, and you don’t have an available network jack. For example, suppose

one of your users has a short-term need for a second computer, but there’s

only one network jack in the user’s office. Rather than pulling a new cable to

the user’s office, just plug a cheap switch into the existing jack and then plug

both of the computers into the switch.



The Complete Documentation of the

Network on Tablets of Stone

I mention several times in this book the importance of documenting your network. Don’t spend hours documenting your network and then hide the documentation under a pile of old magazines behind your desk. Put the binder

in the closet with the other network supplies so that you and everyone else

always know where to find it. And keep backup copies of the Word, Excel,

Visio, or other documents that make up the network binder in a fireproof safe

or at another site.

Don’t you dare chisel passwords into the network documentation, though.

Shame on you for even thinking about it!





If you decide to chisel the network documentation onto actual stone tablets,

consider using sandstone. It’s attractive, inexpensive, and easy to update (just

rub out the old info and chisel in the new). Keep in mind, however, that sandstone is subject to erosion from spilled Diet Coke. Oh, and make sure that you

store it on a reinforced shelf.



www.it-ebooks.info



413



414



Part VII: The Part of Tens



The Network Manuals and Disks

In the Land of Oz, a common lament of the Network Scarecrow is, “If I only

had the manual.” True, the manual probably isn’t a Pulitzer Prize candidate,

but that doesn’t mean you should toss it in a landfill, either.

Put the manuals and disks for all the software you use on your network where

they belong — in the closet with all the other network tools and artifacts.



Ten Copies of This Book

Obviously, you want to keep an adequate supply of this book on hand to

distribute to all your network users. The more they know, the more they stay

off your back.

Sheesh, 10 copies may not be enough — 20 may be closer to what you need.



www.it-ebooks.info



Index

• Symbols and Numerics •

/ (forward-slash character), 375

\ (backslash), 375

10/100/1000 Mpbs components, 109

802.11 standards, 152–153

2600 The Hacker Quarterly (magazine), 288



•A•

accelerometer

in Android devices, 269

in iOS devices, 260

Access Control List (ACL), 201

Access databases, networking, 58–59

access points (APs), setting, 155–157

accessibility, of cloud computing, 250

accessing

cloud, 255–256

files, 55

network files, 55–56

Outlook Web App, 272

Public Folder, 50

restricting access to certain

computers, 190

account restrictions, for users, 329

account status, 329

accounting services, using in the

cloud, 248

ACL (Access Control List), 201

acquiring software tools for network

administrators, 286–287

activating built-in firewalls

in Windows 7, 145–146

in Windows 8, 145–146

in Windows XP, 144–145

Active Directory (AD), 168, 184, 213

Active Directory Users and Computers

(ADUC), 213

ActiveSync, enabling, 262–263

Activities Overview (GNOME desktop), 380

AD (Active Directory), 168, 184, 213



adding

members to groups, 196–197

network printers, 35–36

ad-hoc networks, 148, 158

ADMIN$, 203

Administrator account

about, 330

password, 179, 328

securing, 328

administrators, network

about, 18–19, 281, 289–290

acquiring software tools for, 286–287

building libraries for, 287–288

choosing part-time, 283–284

duties of, 282–283

managing network users, 285

on network performance, 349–350

pursuing certification, 288–289

“Three Ups of Network Management,”

284–285

ADUC (Active Directory Users and

Computers), 213

Alarm Clock application (Android), 269

AlohaNet, 151

Amazon CloudFront, 254

Amazon Elastic Computer Cloud

(Amazon EC2), 254

Amazon Simple Queue Service

(Amazon SQS), 254

Amazon Simple Storage Service

(Amazon S3), 254

Amazon Virtual Private Cloud

(Amazon VPC), 254

Amazon Web Service (AWS), 254

AND operation, 85

Android devices

about, 258, 267–268

Android OS, 268–269

core applications, 269

integrating with Exchange, 270

ANSI/EIA Standard 568, 110–111

antennas, 150–151



www.it-ebooks.info



Tài liệu bạn tìm kiếm đã sẵn sàng tải về

X. Thou Shalt Write Down Thy Network Configuration upon Tablets of Stone

Tải bản đầy đủ ngay(0 tr)

×