Configuring Your Network for DHCP

Chapter 26 Ten Big Network Mistakes In This Chapter 䊳 Skimping on cable 䊳 Turning off or restarting a server while users are logged on 䊳 Deleting important files that live on the server 䊳 Copying a file from the server, changing it, and then copying it back 䊳 Sending something to the printer again just because it didn’t print the first time 䊳 Unplugging a cable while the computer is on 䊳 Always blaming the network 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 plea- sure 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, you should invest in a professional-quality cable installation, complete with wall-mounted jacks, patch panels, and high- quality hubs. It is tempting to cut costs by using the cheapest hubs and by stringing inexpensive cable directly from the hubs to each computer on the network. But in the long run, that approach will 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: ⻬ A good cable installation will last 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. ⻬ Installing cable is hard work. No one enjoys going up in the attic, poking his or her 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. ⻬ Your network users may be satisfied with 100Mbps 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 plain Cat5 cable instead of more expensive Cat5e cable, you’ll have to replace it later. ⻬ 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 wires inside the network cable are solid wire, which is designed to last for a long time — provided it doesn’t get handled much. If you run solid- wire cable directly to a computer, the wire will be stressed each time someone unplugs the cable. Even just dusting behind the computer which some people actually do can jostle the cable. Sooner or later, one of the wires inside the cable will break. Patch cables are made with stranded rather than solid wire, so they can tolerate a lot of handling without breaking. And if a patch cable does fail, you can replace it your- self for just a few dollars. For more information about professional touches for installing cable, see Chapter 9. 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 press- ing its reset button can have the same disastrous effect. 356 Part VI: The Part of Tens 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 peer- to-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 your computer off or restart it. Someone may be accessing a file or printer on your computer at that very moment. Before turning off or restarting a server computer, find out whether anyone is logged on. If so, politely ask him or her to log off. Also, remember that 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. That means 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? 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. 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. 357

Chapter 26: Ten Big Network Mistakes

Copying a file to a local drive is an okay thing to do, but not if you plan on updating the file and copying it back. 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. Unplugging a Cable While the Computer Is On Bad idea If for any reason you need to unplug a cable from behind your com- puter, turn your computer off first. You don’t want to fry any of the delicate electronic parts inside your computer, do you? If you need to unplug the network cable, you should wait until all the comput- ers on the network are off. This is especially true if your network is wired with Thinnet coax cable; it’s not such a big deal with twisted-pair cable. Note: With Thinnet cable, you can disconnect the T-connector from your com- puter as long as you don’t disconnect the cable itself from the T-connector. Assuming That the Server Is Safely Backed Up Some users make the unfortunate assumption that the network somehow rep- resents an efficient and organized bureaucracy worthy of their trust. 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 sur- prise inspection one day: Burst into the computer room wearing white gloves 358 Part VI: The Part of Tens and demand to see the backup tapes. Check the tape rotation to make sure that more than one day’s worth of backups are 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 floppy disks frequently — or, better yet, to a CD-RW disc. 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. Therefore 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. 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 one of these devices into the network. Then, your wireless notebook PC or hand-held device can instantly join the network. The trouble is, so can anyone else within about 1 ⁄ 4 mile of the wireless access point. That means that 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 10. 359

Chapter 26: Ten Big Network Mistakes

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 net- work sails, you can’t access any network devices. You can’t get files from net- work 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. Always Blaming the Network Some people treat the network kind of like the village idiot who can be blamed whenever anything goes wrong. Networks do 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? 360 Part VI: The Part of Tens Chapter 27 Ten Networking Commandments In This Chapter 䊳 Backing up and cleaning up hard drives 䊳 Scheduling downtime for maintenance 䊳 Keeping spare parts 䊳 Training users 䊳 Recording your network configuration B lessed is the network manager who walks not in the counsel of the igno- rant, nor stands in the way of the oblivious, nor sits in the seat of the greenhorn, but delights in the Law of the Network and meditates on this Law day and night.” — Networks 1:1 And so it came to pass that these Ten Networking Commandments were passed down from generation to generation, to be worn as frontlets between the computer geeks’ eyes taped on the bridges of their broken glasses and written upon their doorposts. Obey these commandments, and it shall go well with you, with your children, and with your children’s children. I. Thou Shalt Back Up Thy Hard Drive Religiously Prayer is a good thing, but when it comes to protecting the data on your net- work, nothing beats a well-thought-out schedule of backups followed reli- giously. If this were an actual network Bible, a footnote here would refer you back to related verses in Chapter 15.