Lowe D. Networking For Dummies
Подождите немного. Документ загружается.
Book III
Chapter 1
Help Wanted: Job
Description for a
Network Administrator
177
Discovering Software Tools for Network Administrators
each other. (You can run net diag from an MS-DOS prompt.) For TCP/
IP networks, you can use the TCP/IP diagnostic commands summarized
in Table 1-1. For more information about these commands, check out
Book IV, Chapter 6.
Table 1-1 TCP/IP Diagnostic Commands
Command What It Does
arp
Displays address resolution information used by the Address
Resolution Protocol (ARP).
hostname
Displays your computer’s host name.
ipconfig
Displays current TCP/IP settings.
nbtstat
Displays the status of NetBIOS over TCP/IP connections.
netstat
Displays statistics for TCP/IP.
nslookup
Displays DNS information.
ping
Verifies that a specified computer can be reached.
route
Displays the PC’s routing tables.
tracert
Displays the route from your computer to a specified host.
✦ System Information: The System Information program that comes with
Windows is a useful utility for network managers.
✦ Hotfix Checker: Another handy tool available from Microsoft is the
Hotfix Checker, which scans your computers to see what patches need
to be applied. You can download the Hotfix Checker free of charge from
Microsoft’s Web site. Just go to www.microsoft.com and search for
hfnetchk.exe.
✦ Microsoft Baseline Security Analyzer: If you prefer GUI-based tools,
check out Microsoft Baseline Security Analyzer. You can download it
from Microsoft’s Web site free of charge. To find it, go to www.micro
soft.com and search for Microsoft Baseline Security Analyzer.
✦ A utility program: I suggest that you get one of those 100-in-1 utility
programs, such as Symantec’s Norton Utilities. Norton Utilities includes
invaluable utilities for repairing damaged hard drives, rearranging the
directory structure of your hard drive, gathering information about your
computer and its equipment, and so on.
Never use a hard drive repair program that wasn’t designed to work
with the operating system or version that your computer uses or the file
system you’ve installed. Any time that you upgrade to a newer version of
your operating system, you should also upgrade your hard drive repair
programs to a version that supports the new operating system version.
19_625873-bk03ch01.indd 17719_625873-bk03ch01.indd 177 9/21/10 10:12 PM9/21/10 10:12 PM
178
Building a Library
✦ A protocol analyzer: A protocol analyzer is a program that’s designed to
monitor and log the individual packets that travel along your network.
(Protocol analyzers are also called packet sniffers.) You can configure
the protocol analyzer to filter specific types of packets, watch for spe-
cific types of problems, and provide statistical analysis of the captured
packets. Most network administrators agree that Sniffer, by Network
General (www.networkgeneral.com), is the best protocol analyzer
available. However, it’s also one of the most expensive. If you prefer a
free alternative, check out Ethereal, which you can download free from
www.ethereal.com.
✦ Network Monitor: All current versions of Windows include a program
called Network Monitor that provides basic protocol analysis and can
often help solve pesky network problems.
Building a Library
One of Scotty’s best lines in the original Star Trek series was when he
refused to take shore leave so he could get caught up on his technical jour-
nals. “Don’t you ever relax?” asked Kirk. “I am relaxing!” Scotty replied.
To be a good network administrator, you need to read computer books. Lots
of them. And you need to enjoy doing it. If you’re the type who takes computer
books with you to the beach, you’ll make a great network administrator.
You need books on a variety of topics. I’m not going to recommend specific
titles, but I do recommend that you get a good, comprehensive book on each
of the following topics:
✦ Network security and hacking
✦ Wireless networking
✦ Network cabling and hardware
✦ Ethernet
✦ Windows Server 2003 or 2008
✦ Windows XP or Vista
✦ Linux
✦ TCP/IP
✦ DNS and BIND
✦ Sendmail
✦ Exchange Server
19_625873-bk03ch01.indd 17819_625873-bk03ch01.indd 178 9/21/10 10:12 PM9/21/10 10:12 PM
Book III
Chapter 1
Help Wanted: Job
Description for a
Network Administrator
179
Getting Certified
In addition to books, you may also want to subscribe to some magazines to
keep up with what’s happening in the networking industry. Here are a few
you should probably consider, along with their Web addresses:
✦ InformationWeek: www.informationweek.com
✦ InfoWorld: www.infoworld.com
✦ Network Computing: www.networkcomputing.com
✦ Network World: www.networkworld.com
✦ 2600 (a great magazine on computer hacking and security):
www.2600.com
The Internet is one of the best sources of technical information for network
administrators. You’ll want to stock your browser’s Favorites menu with
plenty of Web sites that contain useful networking information. In addi-
tion, you may want to subscribe to one of the many online newsletters that
deliver fresh information on a regular basis via e-mail.
Getting Certified
Remember the scene near the end of The Wizard of Oz when the Wizard
grants the Scarecrow a diploma, the Cowardly Lion a medal, and the Tin Man
a testimonial?
Network certifications are kind of like that. I can picture the scene now:
The Wizard: “And as for you, my network-burdened friend, any geek with
thick glasses can administer a network. Back where I come from, there
are people who do nothing but configure Cisco routers all day long.
And they don’t have any more brains than you do. But they do have one
thing you don’t have: certification. And so, by the authority vested in
me by the Universita Committeeatum E Pluribus Unum, I hereby confer
upon you the coveted certification of CND.”
You: “CND?”
The Wizard: “Yes, that’s, uh, Certified Network Dummy.”
You: “The Seven Layers of the OSI Reference Model are equal to the Sum
of the Layers on the Opposite Side. Oh, rapture! I feel like a network
administrator already!”
My point is that certification in and of itself doesn’t guarantee that you
really know how to administer a network. That ability comes from real-
world experience — not exam crams.
19_625873-bk03ch01.indd 17919_625873-bk03ch01.indd 179 9/21/10 10:12 PM9/21/10 10:12 PM
180
Getting Certified
Nevertheless, certification is becoming increasingly important in today’s
competitive job market. So you may want to pursue certification — not just
to improve your skills, but also to improve your resume. Certification is
an expensive proposition. Each test can cost several hundred dollars, and
depending on your technical skills, you may need to buy books to study or
enroll in training courses before you take the tests.
You can pursue two basic types of certification: vendor-specific certifica-
tion and vendor-neutral certification. The major software vendors such as
Microsoft and Cisco provide certification programs for their own equipment
and software. CompTIA, a nonprofit industry trade association, provides the
best-known vendor-neutral certification.
The following sections describe some of the certifications offered by
CompTIA, Microsoft, Novell, and Cisco.
CompTIA
www.comptia.org
✦ A+ is a basic certification for an entry-level computer technician. To
attain A+ certification, you have to pass two exams: one on computer
hardware, the other on operating systems.
✦ Linux+ covers basic Linux skills such as installation, operations, and
troubleshooting. This certification is vendor neutral, so it doesn’t
depend on any particular version of Linux.
✦ Network+ is a popular vendor-neutral networking certification. It covers
four major topic areas: Media and Topologies, Protocols and Standards,
Network Implementation, and Network Support.
✦ Server+ covers network server hardware. It includes details such as
installing and upgrading server hardware, installing and configuring a
NOS, and so on.
✦ Security+ is for security specialists. The exam topics include general
security concepts, communication security, infrastructure security,
basics of cryptography, and operational/organizational security.
Microsoft
www.microsoft.com/learning/mcp
✦ MCTS, or Microsoft Certified Technology Specialist, is a certification in a
specific Microsoft technology or product.
✦ MCITP, or Microsoft Certified IT Professional, is a certification in deploy-
ing and maintaining IT infrastructure.
19_625873-bk03ch01.indd 18019_625873-bk03ch01.indd 180 9/21/10 10:12 PM9/21/10 10:12 PM
Book III
Chapter 1
Help Wanted: Job
Description for a
Network Administrator
181
Gurus Need Gurus, Too
✦ MCSE, or Microsoft Certified Systems Engineer, is a prestigious certifica-
tion for networking professionals who design and implement networks.
To gain this certification, you have to pass a total of seven exams.
Microsoft offers separate Windows 2000 Server and Windows Server
2003 certification tracks.
✦ MCSA, or Microsoft Certified System Administrator, is for networking
professionals who administer existing networks.
Cisco
www.cisco.com/certification
✦ CCNA, or Cisco Certified Network Associate, is an entry-level apprentice
certification. A CCNA should be able to install, configure, and operate
Cisco equipment for small networks (under 100 nodes).
✦ CCNP, or Cisco Certified Network Professional, is a professional-level
certification for Cisco equipment. A CCNP should be able to install, con-
figure, and troubleshoot Cisco networks of virtually any size.
✦ CCDA, or Cisco Certified Design Associate, is an entry-level certification
for network design.
✦ CCDP, or Cisco Certified Design Professional, is for network design pro-
fessionals. Both the CCDA and CCNA certifications are prerequisites for
the CCDP.
✦ CCIP, or Cisco Certified Internetwork Professional, is a professional-level
certification that emphasizes advanced use of IP and related protocols
to create intranetworks.
✦ CCIE, or Cisco Certified Internetwork Expert, is the top dog of Cisco
certifications.
✦ And much more! There are many more Cisco certifications to choose
from, including certification for security, voice technology, wireless net-
working, and more.
Gurus Need Gurus, Too
No matter how much you know about computers, plenty of people know
more than you do. This rule seems to apply at every rung of the ladder of
computer experience. I’m sure that a top rung exists somewhere, occupied
by the world’s best computer guru. However, I’m not sitting on that rung,
and neither are you. (Not even Bill Gates is sitting on that rung. In fact, Bill
Gates got to where he is today by hiring people on higher rungs.)
19_625873-bk03ch01.indd 18119_625873-bk03ch01.indd 181 9/21/10 10:12 PM9/21/10 10:12 PM
182
Helpful Bluffs and Excuses
As the local computer guru, one of your most valuable assets can be a
knowledgeable friend who’s a notch or two above you on the geek scale.
That way, when you run into a real stumper, you have a friend to call for
advice. Here are some tips for handling your own guru:
✦ In dealing with your own guru, don’t forget the Computer Geek’s Golden
Rule: “Do unto your guru as you would have your own users do unto
you.” Don’t pester your guru with simple stuff that you just haven’t
spent the time to think through. If you have thought it through and can’t
come up with a solution, however, give your guru a call. Most computer
experts welcome the opportunity to tackle an unusual computer prob-
lem. It’s a genetic defect.
✦ If you don’t already know someone who knows more about computers
than you do, consider joining your local PC users’ group. The group
may even have a subgroup that specializes in your networking software
or may be devoted entirely to local folks who use the same networking
software that you use. Odds are good that you’re sure to make a friend
or two at a users’ group meeting. Also, you can probably convince your
boss to pay any fees required to join the group.
✦ If you can’t find a real-life guru, try to find an online guru. Check out
the various computing newsgroups on the Internet. Subscribe to online
newsletters that are automatically delivered to you via e-mail.
Helpful Bluffs and Excuses
As network administrator, you just won’t be able to solve a problem some-
times, at least not immediately. You can do two things in this situation. The
first is to explain that the problem is particularly difficult and that you’ll
have a solution as soon as possible. The second solution is to look the user
in the eyes and, with a straight face, try one of these phony explanations:
✦ Blame it on the version of whatever software you’re using. “Oh, they
fixed that with version 39.”
✦ Blame it on cheap, imported memory chips.
✦ Blame it on Democrats. Or Republicans. Or hanging chads. Whatever.
✦ Blame it on oil company executives.
✦ Blame it on global warming.
✦ Hope that the problem wasn’t caused by stray static electricity. Those
types of problems are very difficult to track down. Tell your users that
not properly discharging themselves before using their computers can
cause all kinds of problems.
19_625873-bk03ch01.indd 18219_625873-bk03ch01.indd 182 9/21/10 10:12 PM9/21/10 10:12 PM
Book III
Chapter 1
Help Wanted: Job
Description for a
Network Administrator
183
Helpful Bluffs and Excuses
✦ You need more memory.
✦ You need a bigger hard drive.
✦ You need a faster processor.
✦ Blame it on Jar-Jar Binks.
✦ You can’t do that in Windows Vista.
✦ You can only do that in Windows Vista.
✦ Could be a virus.
✦ Or sunspots.
✦ No beer and no TV make Homer something something something. . . .
19_625873-bk03ch01.indd 18319_625873-bk03ch01.indd 183 9/21/10 10:12 PM9/21/10 10:12 PM
Book III: Network Administration and Security
184
19_625873-bk03ch01.indd 18419_625873-bk03ch01.indd 184 9/21/10 10:12 PM9/21/10 10:12 PM
Chapter 2: Security 101
In This Chapter
✓ Assessing the risk for security
✓ Determining your basic security philosophy
✓ Physically securing your network equipment
✓ Figuring out user account security
✓ Using other network security techniques
B
efore you had a network, computer security was easy. You simply
locked your door when you left work for the day. You could rest easy,
secure in the knowledge that the bad guys would have to break down the
door to get to your computer.
The network changes all that. Now, anyone with access to any computer on
the network can break into the network and steal your files. Not only do you
have to lock your door, but you also have to make sure that other people
lock their doors, too.
Fortunately, network operating systems have built-in provisions for network
security. This situation makes it difficult for someone to steal your files,
even if they do break down the door. All modern network operating systems
have security features that are more than adequate for all but the most
paranoid users.
When I say more than adequate, I mean it. Most networks have security
features that would make even Maxwell Smart happy. Using all these secu-
rity features is kind of like Smart insisting that the Chief lower the “Cone of
Silence.” The Cone of Silence worked so well that Max and the Chief couldn’t
hear each other! Don’t make your system so secure that even the good guys
can’t get their work done.
If any of the computers on your network are connected to the Internet, you
have to contend with a whole new world of security issues. For more infor-
mation about Internet security, see Chapter 4 of this minibook. Also, if your
network supports wireless devices, you have to contend with wireless secu-
rity issues. For more information about security for wireless networks, see
Book V, Chapter 2.
20_625873-bk03ch02.indd 18520_625873-bk03ch02.indd 185 9/21/10 10:13 PM9/21/10 10:13 PM
186
Do You Need Security?
Do You Need Security?
Most small networks are in small businesses or departments where every-
one knows and trusts everyone else. Folks don’t lock up their desks when
they take a coffee break, and although everyone knows where the petty cash
box is, money never disappears.
Network security isn’t necessary in an idyllic setting like this one, is it? You
bet it is. Here’s why any network should be set up with at least some mini-
mal concern for security:
✦ Even in the friendliest office environment, some information is and
should be confidential. If this information is stored on the network, you
want to store it in a directory that’s available only to authorized users.
✦ Not all security breaches are malicious. A network user may be rou-
tinely scanning through his or her files and come across a filename that
isn’t familiar. The user may then call up the file, only to discover that it
contains confidential personnel information, juicy office gossip, or your
résumé. Curiosity, rather than malice, is often the source of security
breaches.
✦ Sure, everyone at the office is trustworthy now. However, what if some-
one becomes disgruntled, a screw pops loose, and he or she decides to
trash the network files before jumping out the window? What if someone
decides to print a few $1,000 checks before packing off to Tahiti?
✦ Sometimes the mere opportunity for fraud or theft can be too much for
some people to resist. Give people free access to the payroll files, and
they may decide to vote themselves a raise when no one is looking.
✦ If you think that your network doesn’t contain any data that would be
worth stealing, think again. For example, your personnel records prob-
ably contain more than enough information for an identity thief: names,
addresses, phone numbers, Social Security numbers, and so on. Also,
your customer files may contain your customers’ credit card numbers.
✦ Hackers who break into your network may not be interested in stealing
your data. Instead, they may be looking to plant a Trojan horse program
on your server, which enables them to use your server for their own
purposes. For example, someone may use your server to send thou-
sands of unsolicited spam e-mail messages. The spam won’t be traced
back to the hackers; it will be traced back to you.
✦ Finally, remember that not everyone on the network knows enough
about how Windows and the network work to be trusted with full access
to your network’s data and systems. One careless mouse click can wipe
out an entire directory of network files. One of the best reasons for acti-
vating your network’s security features is to protect the network from
mistakes made by users who don’t know what they’re doing.
20_625873-bk03ch02.indd 18620_625873-bk03ch02.indd 186 9/21/10 10:13 PM9/21/10 10:13 PM