Home Networking Tips Advice

8/14/2019 Home Networking Tips Advice

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2008 Watching The Net Web: http://www.watchingthenet.com Page: 1

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Hom e Networki n g Ti ps & Ad vi ce

What Is a Home Network?...........................................................................................2

Home Networking Is For You .....................................................................................3Networking 101 .....................................................................................................5How Does Home Networking Work? ...............................................................6Networking Options..............................................................................................7Wireless Network Pros and Cons .....................................................................8Protocols Made Easy ..........................................................................................10Essential Home Networking Equipment.......................................................11Connecting to the Internet ..............................................................................12Guidelines For Building A Simple Home Network.....................................14Setting Up and Using a Shared Printer........................................................15

File Sharing...........................................................................................................17Security Issues and Guidelines ......................................................................18Firewalls .................................................................................................................19Troubleshooting a Home Network .................................................................20

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What Is a Home Network?

A home network is a computer network you have in your home. True, but not veryhelpful, eh? So, lets dig a little deeper.

Most people know by now that in order for onecomputer to share information with another, itsnecessary to connect them together in some way.Those connections and the computers that are part ofthem form a network. Just like a spider web, when thetrapped fly tugs on one part, a signal is sent to thespider at the other end.

In the case of a home network, the web is made up ofeither cables or radio beams. Those two basic options make up the differencebetween what is called a cabled or wired network versus a wireless network. Asrecently as five years ago, a lifetime in the computer world, the wireless option wascomplicated and expensive. Today, wireless home networks are often less expensiveand easier to create.

At different points along the web there are junctions called nodes. Those nodes canbe in the form of computers, switches or routers.


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Switches provide a place to plug the cables in that allow a physical connectionbetween communicating computers. Routers perform a similar purpose but withmore functions, such as the ability to connect multiple networks together and (as thename suggests) route traffic intelligently between them.

In many cases, computers themselves can perform thosefunctions. Software within the system can use the networkcards in each computer, with a simple switch in between, toallow communication between them. Though routers havebecome commonplace, thats still possible and if your needsare fairly simple it can be the cheapest, easiest way to createa home network.

But computers, switches and routers arent the only possiblecomponents of a home network. Familiar devices that go under the general name ofperipherals are often part of the home web.

One of the reasons for undertaking the expense and effort of creating a network is

often to share folders, printer, fax or scanner among multiple computers. If yousplurged for a color laser printer or a fax machine at home, you save money by onlyneeding to purchase one device each, instead of multiple printers and faxes for eachcomputer. A home network allows sharing those devices.

As part of the basic home network system, youll often want to include softwareand/or hardware known as a firewall. A firewall allows for passing some informationsent by trusted sources, but blocks other types of data, or that sent from any othersource.

With wireless networks or any home network connected to the Internet, they are amust. Fortunately, routers typically contain some inherent firewall functions. Evensoftware within the OS today can usually perform that function.

Putting all these different pieces together in a coherent way that allows you to sendand receive files, share printers and more is the process of creating a home network.Of course, doing it in a way that doesnt get you tangled up in a sticky web requiresa bit of homework.

Home Networking Is For You

Not too many years ago building a home network was strictly for professionals andtrue computer geeks. The cost, the complexity and other factors made it a veryrough road for anyone else.

But the situation has changed.


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Today, the costs have come down on every component. Wireless is notmuch more expensive, and sometimes less, than cabled gear. A bit ofCat 5 Ethernet cable costs not much more than plain stereo equipmentwire. A hub costs a few dollars. Even routers, once $200 or more arenow available for little more than the cost of an ordinary switch.

At the same time, speeds have increased.

Reliability has improved for both cabled and wireless networks. The latter were oncejust for experiments by hobbyists. A cordless phone call, a wall or just a solar flarehiccup could easily knock your network offline. Distances were limited to a fewmeters, making wireless networks much less attractive for networking the wholehome. Now, they can cover the whole of a large, two story home with ease.

But perhaps best of all, besides the lower cost and better performance, homenetworking is now simpler than ever. Todays gear comes with better instructions,ones that dont assume you are a computer or networking expert. The software andhardware both are simpler to configure. The diagnostic tools are easier to use than in

times past.

At the same time, most people have increased their basic computerknowledge by leaps and bounds. With the Internet, cell phones,iPods being a daily part of everyones lives, the intimidation factoris at an all time low. Everyone today knows how to use email. Mostpeople know what HTTP is, how to ping something and other thingsonce considered esoteric. Discussing routers, IP addresses andother aspects is no longer just for wild eyed guys with glasses.

Security consciousness has been raised, too. As a result of thousands of articles oncredit card or identity theft and other computer related issues, people are much

better informed and more cautious. They may not follow all the standardrecommendations touted by security professionals, but theyre no longer indifferent.Anyone who has ever been hit by a computer virus, which is just about everyonetoday, has seen first hand the need for some efforts in this area.

There are still a few minor hurdles to overcome. The biggest one is usually justabsorbing a fair number of unfamiliar terms, such as protocol, NIC (NetworkInterface Card) and other related words. Once that wall is breached, the rest ispretty straightforward.

Even adding an Internet connection to the home network, so that it can be shared byall systems instead of just one, is very simple today. A little bit of homework,sometimes a modest amount of troubleshooting, and youre in business.

So get in gear and start hooking together those computers ownedby each member of the family. Youll find that printer sharing iseasy. Youll be able to pass files without emailing them from onesystem and downloading them from another. Youll find yoursecurity enhanced. Most of all, youll have the same kind of funthat used to be limited to computer experts. Who wouldnt wantthat?


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Networking 101

A network is like a spider web, the basic reason that the Internet(WWW World Wide Web) is often called that. Its a series of lines(called routes) that have intermediate and end points (called nodes)that connect devices together. Those connections and routes arewhat allow the devices to share, input or output information acrossthe network.

Along those routes, signals flow that contain information of interestto the network users. Like a trapped fly that tugs on a part of theweb, the disturbance is sent down the line, through nodes, to thespider at another point on the web. Unfortunately for the fly, thespider often sends back a reply.

Unlike a spider web, though, a computer network sends and receives those

disturbances in the form of something called packets. There are other ways toperform the same function, but today almost all networks operate as explainedbelow.

Software and hardware on the network cooperate to pass those packets. Packets arechunks of information containing your data wrapped in control information. Thatcontrol data at the front and back of your data allows routers and computers to knowwhere and how to send your data.

In most commercial and home networks, the method uses something called IP, orInternet Protocol. Every device on the network gets assigned an address in the formof what is called a dotted octet, such as 209.131.36.158. In the home, thoseaddresses are usually in a range of:

10.0.0.0 through 10.255.255.255, or172.16.0.0 through 172.31.255.255, or192.168.0.0 through 192.168.255.255

Those constitute what are called Private Addresses, since they cant be sentunmodified over the public networks that form the Internet. Theyre used by routers,computers and peripherals in your home network.

Private commercial networks, such as those inside companies large and small alsouse these same address ranges. Something called network address translation, NAT,at a device called a boundary router allows many companies and homes to use the

same range without accidentally passing information to and from one another overthe Internet.

Note that your home computer may have a very different address,such as 70.31.192.243. This is often the case because a singlecomputer connected to the Internet gets an address assigned by theISP, Internet Service Provider. You then dont really have just a homenetwork, but are a paying customer of a commercial network.


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When each device - each computer, router, printer - is assigned its own address, thesoftware and hardware can figure out where data is coming from and should go to.Its what makes possible communication without confusion.

The router software and/or hardware, in cooperation with networking hardware andsoftware in each device, routes the data to and from the proper devices using those

addresses. The method is in principle the same as that used by the postal system toroute letters from one home or business to another.

How Does Home Networking Work?

A home network is a set of hardware and software that allows computer-basedcommunication. File sharing, printer sharing and other input and output is a typicalpart of the home network. But how does it perform those functions?

A home network functions in a nearly identical way to that used by

private companies when they create what is known as a Local AreaNetwork (LAN). Designations called IP addresses, and someassociated easy-for-humans-to-remember names (often calledhost names) are used to know who and where everything is.

For example, when 10.1.1.5 (Computer-Jack) sends a file to 10.1.1.6 (Computer-Jill), the software and hardware cooperate to know where and how to send the filefrom Jack to Jill.

The idea is, in principle, the same as that used by the post office. Each home has anaddress and a letter sent from one home is routed to another by using that address.The return address on the envelope makes it possible to know where to respond.Home computer networks operate the same way, even calling the routing data usedan envelope that surrounds the data (the words on the letter).

Physically, a home network comes in two basic types: cabled and wireless.

In a cabled network, wire bundles called Ethernet cables with connectors on eachend plug into either a NIC (network interface card) in the computer, printer, fax, or into a switch/router. Switches or hubs are simplified devices that allow physicalconnections between components of the network. Routers contain additionalsoftware and circuitry to perform more complex functions, such as connecting to theInternet.

A wireless network operates the same way, except there is no

need for cables. Instead, small devices called transceivers(transmitter-receiver) send and accept information by radiosignals.

Suppose for example that you want two computers within ahome network to both be able to print to the same printer. Thereare two basic ways to make that possible. In one set up the printer is physicallyattached to one of the computers. The alternate set up connects the printer to thenetwork itself, not to any individual computer.


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In the first arrangement, the printer is called local, but shareable. Just as you mightmake files on one computer accessible to another, so its possible to allow a remotecomputer to print to the locally attached device. Computer-Jack then simply sharesthe printer by using software on the hosting system, Computer-Jill.

In the more typical case today, the printer has its own NIC and is attached to aswitch or router via Ethernet cables or a wireless transceiver. Each computer on thenetwork then sees the printer as a device it can use.

Scanners, fax machines and even other computers (file servers, for example)operate essentially the same way. Each device gets an address and a name.Software on the device allows it to be configured to make its function accessible tomultiple computers on the same network.

Networking Options

When you start to design your home network, youll beimmediately faced with a wide array of choices. Many of themhave cryptic names and obtuse descriptions. But dont be put offby all the techno-babble. Make an effort to get familiar withsome of the names because theyre associated with options thataffect the design and value of your home network.

The first, basic choice is between a cabled network and a wireless one. The choiceused to be made for most everyone, given the once high prices and complexity ofwireless equipment. But costs have come down and putting a wireless networktogether today is no more complicated than the more traditional type.

Cabled networks today usually run along Ethernet cables. MostEthernet cabling used is designated by the name: Cat-5. There isanother option, though, and thats to use fiber optic cabling. Forhome network designers, the extra cost and potential reliabilityissues arent worth the benefits.

Ethernet cables will support speeds ranging from the traditional 10 Mb or 100 Mb upto 1 Gb or more. (Here, 10 Mb = 10 megabits/sec = 10/8 megabytes per second.)10 Gb is not unknown and one company has now produced a wired device thatoperates at a theoretical speed of 100 Gb. (1 Gb = 1 gigabit/sec = 1/8 x 1024megabytes per second = 128 MB/s.)

The speed is theoretically limited by the cable, but in practice theattached devices are more of a limiting factor. Other factors, suchas number of simultaneous users, protocol used and other factorsare often even more important in real-world applications. Thefaster speeds are typically found only in professional networks,however.

Wireless devices are often 802.11b or 802.11g type today. Thetechnical definitions are complex, but the practical meaning for the home network


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designer is simple: 802.11b operates at 2.4 GhZ and 11 Mb and 802.11g at 2.44GHz/54 Mb.

Both numbers are important, the frequency (measured in Ghz or 1,024 million cyclesper second) and the throughput, in megabits. (1 Byte = 8 bits)

The frequency gives you a clue about the likelihood of interference. Somecordless phones and other popular home devices can interfere with yournetwork. That means that when the phone rings and you answer it, yournetwork may see a hiccup. The problem tends to occur more often withwireless cards in laptops, however.

The throughput is important, since the numbers are theoretical ratings.The real data transfer rate of, for example, 802.11b tends to be between

6-7 Mb/s, despite the rated speed of 11 Mb/s. For comparison, thats roughly 1/5 to1/2 the speed of a DSL or cable Internet connection. So, if you know how long ittakes you to download, say, a 10 megabyte file off the Internet, you can easilyestimate how fast data will get around your home network.

Other systems have been in the experimental stage for several years. One uses thewiring in your home to carry network signals. All you would have to do is plug aspecial device into an electrical outlet then plug your computer, printer into that viaa short cable. Though, some use wireless technology as part of the system. Itspossible to obtain the equipment, but major vendors dont yet offer this option. Fornow, its best for most home network designers to stick to the standard choices.

Wireless Network P ros and Cons

Five years ago, a lifetime in the computer world, the decision ofwhether or not to go wireless would have been made for most homenetwork builders. The cost and complexity, relatively low reliabilityand lower speed would have made a wireless network valuable onlyfor the hobbyist. Someone who wanted to build one could have a lotof fun from the exercise. But for practical use, it was a second choiceat best.

Today, the situation has changed. Wireless equipment has comedown considerably in price, relatively speaking. The cost of standard Ethernet cables,switches, routers is typically still less than their wireless counterparts. But thedifference has shrunk quite a lot.

At the same time, the performance and reliability cost/benefit ratio has shifted.

Even five years ago it was easily possible to build a homenetwork that used 100 Mb technology. (100 Mb = 100megabits/s = 100 x 1 megabits/8 bits/byte = 12.5megabytes per second.) For more money, then or now,you could build a 1 Gb Ethernet network if you needed theextra bandwidth and speed. That would comfortablysupport several computers transferring data


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simultaneously.

Now, wireless products are very competitive in terms of speed and overallperformance. Even a slower 802.11b wireless router is rated at 11 Mb, whiledelivering real-world throughput of about 6-7 Mb. For only a slightly higher price, onaverage, you can now get an 802.11g router with a rated speed of 54 Mb and newer,

faster models are not far off.

Wireless networks offer the maximum in convenience with, in some respects,simplified construction. Its commonplace for there to be multiple computers in thehome today.

Most people will not want to have their home look like a computerroom. Yet, stringing Ethernet cable around the house inside walls,under carpets or along the floor boards, is a task. Confined to thehome office, it may not be a big deal. Wiring the entire house isanother matter.

With a wireless network, you simply place the wireless router in

some location that is sensible for the devices it is going to support.Then, follow the configuration instructions, and youre in business. The teenager incollege upstairs in her bedroom works just fine at the same time as Mom in thehome office or Dad in the living room. No need to string a wire to the couch or bed.

But there are some limitations and potential downsides. Apart from the higher costand slower speeds, wireless networks may introduce configuration, security andreliability issues.

Though theyve improved vastly, wireless networks can be more difficult toconfigure. Wireless routers sometimes have cryptic configurations. Wired routers cantoo, but it tends to be more so in the case of wireless networks. Youre sometimes

unsure whether the issue is software or simply a signal not being sent/received.

Security has improved too, though there is an inherent hurdle with wirelessnetworks. Since they dont require a physical connection, anyone with a wireless-enabled laptop or cell phone who is nearby can, in theory, access your network. Butif you follow the directions carefully when configuring the router, this problem can beovercome.

Reliability is another area that has gotten much better, though it cant always matcha cabled network. Cable networks can have hiccups, usually when plugging in newdevices. Bad cables or connectors are rare, but they do exist.

But wireless network devices are much more subject to possible interference.Microwave ovens, cordless phones, Bluetooth-enabled devices and other commonhome technology send and receive signals in the same frequency range. Sometimes


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they clash. Charged particle streams from solar flares and other natural phenomenoncan interfere with your signal.

All in all, though, wireless networks offer flexibility and speed that suits the needs ofhome network builders well at affordable prices.

Protocols Made Easy

Home networking throws novices immediately into apool of cryptic names and acronyms. Fortunately,home networks are actually fairly easy to build. Thefirst hurdle is little more than becoming familiar withmany of those names and letters. Once you learn alittle terminology, the rest is often just commonsense and carefully following some directions.

One of the first terms youll encounter, along with agreat many associated acronyms, is the wordprotocol. The technical definition of the word and the acronyms can become verycomplex. But, the meaning for your purposes is really very straightforward.

A protocol is just a set of rules that have been adopted as a standard method fordevices to communicate. For example, the HTTP protocol used by Internet browsersspecifies a detailed list of methods for passing Internet data back and forth. Morefundamentally, TCP/IP (Transmission Control Protocol/Internet Protocol) is a methoddictating how packets get defined and transported on a TCP/IP-based network.

Note that there are various ways, involving other protocols, to establish networksand their rules. IBM was one of the earliest with its SNA network philosophy, whichwas in wide use in business for decades. Though commonly replaced now by TCP/IP,it is still in use around the world. And these two are not the only ones that have beenwidely adopted at one time or another.

While the details are of interest only to professionals and geeks,there are aspects that affect how a home network builder has toproceed. Knowing some of them will help you choose equipmentand design your network intelligently.

For example, one of the central pieces of home network gear (asit is for professional networks) is the router. But routers come in

various types, each associated with a particular protocol. Wireless routers, for

example, may use the 802.11b or 802.11g protocol. The technical definition isntimportant, but knowing that the first is rated at 11 Mb (11 megabits/sec transferrate) versus 54 Mb throughput impacts your network.

Though the first is rated at 11 Mb, like many things, thats the rate under idealizedconditions. The real throughput is about 6-7 Mb. And keep in mind that there are 8bits per byte (equivalent to one character of data). So the actual transfer rate, evenideally, is already only 1/8th of what you actually tend to think of when transferring


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files. Even faster gear that follows the 802.11n standard running at 100 Mb shouldbe available soon.

Similarly, most people have no reason to care about the details of the Ethernetprotocol. But knowing that 802.3 is the standard protocol used in Ethernet networkshelps remove some of the strangeness from yet another cryptic computer number.

At the same time, its helpful to know that 10BaseT is more or less a synonym forwired Ethernet networks that run at 10 Mb (10 megabits/sec). 100BaseT is thestandard for cabled Ethernet networks that use equipment running at 100 Mbps.

Every week there will be a new acronym and a new unfamiliar set of numberscreated. Thats the computer business and network designers are among thegeekiest in the biz. But get familiar with a few of these protocols and related itemsand youll soon be barking them out with the best of them.

Essential Home Networking Equipment

There are two basic types of home network, cabled (or wired)and wireless. Either type you choose will have some basicequipment in common, though the specific type will vary.

First and foremost, in order for any two devices on the networkto communicate, some path has to be established.

In a cabled network, thats done physically by means of wirestrands, usually Ethernet cables. They can be any length up to several hundred feet.There are physical limitations before a switch or router has to be introduced betweencables, but the length is far greater than most home network builders will have toworry about.

In a wireless network, the path may be invisible, but its just as real. In this case,radio waves are used to send and receive signals. In principle, they are subject tointerference just as broadcast TV signals may be. But in practice, within the home,thats rarely a problem.

Rarely, but not never. Things that generate or interfere withradio signals such as microwave ovens, streams of chargedparticles from solar flares, metal inside walls can be a problem.Sometimes, a wall is enough to lessen the effectiveness of thewireless signal.

Next, you need devices that can send and receive the signals thatthose wires or beams will carry.

A NIC (network interface card), usually in the form of an Ethernet card, is a nowfamiliar part of home networking equipment. Theyre often as inexpensive as a fewdollars and come in a range of speeds. Today, 10Mb, 100Mb and 1Gb arecommonplace.


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There are other speeds as well. An 802.11g wireless network, for example, transmitsat 54Mb/s, while 802.11b operates at 11Mb/s. As time progresses and costs comedown, the higher speeds are more and more dominating the market. Higher speedsare available and becoming more common.

A NIC can be the more traditional type that connects to Ethernet cables, or it can be

a wireless card that has a transceiver built-in to send and receive radio signals.

But the NICs in different devices (such as two computers on the network) are rarelyconnected by the cables directly. In almost all cases they run to a switch or, thesedays more often, a router.

A switch or hub is a small device with ports (holes) that cables can be plugged into.Theyre ultra low cost (often just a few dollars) and adequate for simple networksthat dont require a connection to the Internet. More often today, home networkbuilders will use one or more routers.

A router is just what it sounds like, a device that routes traffic. It determines howand where to direct data by using a series of IP addresses (such as 10.1.5.142) andsoftware/hardware designed to receive data from some devices and send data toothers.

Routers come in two basic flavors today, cabled and wireless. Each type comes in avariety of models from different vendors. They have different software, which isusually proprietary and offer different functions. Some for example, may have virus

protection built in. They may vary according to the number of ports, whichdetermines how many devices can be plugged in. Theyll vary according to how fastthey actually operate at, along with variations in rated speed (54Mb rated ~ 6 Mbactual).

There are other devices that may, and usually do, form part of a home network suchas a cable modem, DSL or satellite modem for connecting to the Internet. But thoselisted above are the bare essentials to get started.

Connecting to the I nternet

Most home network builders will not be satisfied just to trade filesamong the computers on the home network. That means they will wantto connect at least one system to the Internet. In the usual scenario,network builders will want all systems on the home network to haveaccess to the Internet as well.

There are multiple ways to do that, each with pros and cons in terms ofcost, complexity, performance, reliability and security.


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Independent Connections

The first, and almost always the most expensive, option is to have multiple,independent connections to the Internet. Few will want to absorb the cost of havingmultiple DSL, cable or satellite modems. Few will want to pay their ISP for double,triple or more connections to the Internet.

But this method does have some advantages.

Each computer that connects will have a completely independent connection, eventhough as part of the same home network they can still share files, printers andother devices. Each computer gets the full security features offered by the ISPwithout any complex configuration on the part of the home network designer. Eachcomputer gets the full bandwidth, so performance is optimal. And you have built-inredundancy. If one connection goes down, you have another that can still access theInternet.

Alternatively, its possible to use one DSL or cable modem, insert a hub inline, andplug multiple computers into the hub. Then purchase independent IP addresses from

the ISP. This only costs one DSL or cable modem, but extra IP addresses are usuallya bit pricey. Performance is still usually very good for each system, provided therouter can handle your average traffic without a big slow down.

Internet Connection Sharing

Another option several steps down in terms of cost comes atthe price of a little bit of complexity. Its possible to use onecomputer as a router and to use Internet Connection Sharingsoftware in Windows or Linux to make the connectionavailable to other computers on the network.

In this scenario, one computer connected to the Internet andassigned a public IP address by the ISP gets an extra NICinstalled. To that second adapter is plugged a cable that runs to a NIC in a secondcomputer. Using Internet Connection Software that comes with Windows or Linux,its possible to configure both systems to share the single Internet connection.

Cheap and semi-reliable. But it has some drawbacks. Any network use on the part ofthe second computer will impact the first one, the one that has the direct connection.All network traffic for the second computer has to be managed by the hardware andsoftware in the computer with the direction connection, so its performance slowsdown. Also, if the first computer fails, or even is just rebooted or shut down, theInternet connection goes away for the second computer.

Router and Hub

With decreasing costs and ease of configuration, another option is becoming the bestfor most people. In this case, a router is connected to the DSL, cable or satellitemodem. It acts as a gateway for all network traffic to and from the Internet by anysystem on the home network.


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Sometimes routers will allow multiple connections, in somecases a hub may be required in order to provide enoughports for all the home network connected devices. But hubsare reliable and cheap, so it adds only a tiny amount ofcomplexity to the design.

With this setup, each user gets the full security availablefrom the ISP and the router acts as a common firewall to

add to that. Most routers will handle the traffic from all users pretty well, provided nosingle user is constantly downloading large files from the Internet.

File sharing between each computer is safer since each is behind the firewall.Network configuration is marginally simpler since you can use DHCP-assigned IPaddresses using the DHCP-server function found in most routers. That way, as youswap laptops and other devices in and out of the network, theres no need to makesure you havent assigned a duplicate static IP address.

Only a short period of homework is required for most home network builders tocatch on how to implement this scenario. The instructions that come with most

routers will provide enough information to set it up. The cost is modest today andprovides the best alternative for most situations.

Guidelines For Building A Simple Home Netw ork

For many people, their computing needs at home are fairlysimple. Even today when its more commonplace for multiplefamily members to have their own computer, the systems areoften stand alone devices. They have little or no need to sharedata. Sneaker net, or sharing data by passing a CD from oneto the next, is often good enough. Emailing over the Internet is,

of course, another now-common method.

But for those who want to take the next step and build their own home network, thetiming is good. Costs have come down and complexity is less than ever. The initialhurdle for most home network wannabees is simply to get over the techno-babblebarrier. Familiarity can help.

The basic equipment needed is fairly simple to understand.Youll need something called Ethernet Cat-5 cable if you plan tobuild a wired network. Just estimate how much you need byplanning out where you want to connect devices to/from and

then add about 20% more. You always need more than youthink you do. For wireless networks, which sometimes costmore, you can skip that requirement.

Those cables or, in the case of wireless networks the radio beams, have to havesomething to connect to. So, youll need a hub or switch or router. A hub is thesimplest and cheapest device. Its just a small device with ports (holes) to plugcables into. A switch looks the same but has slightly more function. A router is morecostly, but has the most features. For connecting to the Internet, it is almost a must.


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Almost because it is possible to use one of the computers to do Internet ConnectionSharing. But its often better to have a dedicated router, rather than consumingresources on one of the computers in the network.

Lastly, you need devices - called adapters - inside the computers, printers, fax

machines that you want to connect to the network. They can be standard 10/100Ethernet NICs (network interface cards) or 802.11 (b or g) wireless cards thatperform the same function in a cable-free network. There are other possbile methodsand associated gear, as well.

With Ethernet, you have two basic choices of speed 10 Mb or 100 Mb. But the pricedifference is so little these days, that its usually pointless to get anything less than100 Mb gear. They typically support older devices that will run only at the slowerspeed. Gigabit Ethernet is an option, but its more expensive than most homenetwork builders may want to pay.

Install, attach and/or setup all hardware according to themanufacturers directions.

Each device on the network will need at least one IP address.These are the dotted octet numbers you may have seen whenaccessing the Internet, such as 70.1.2.125. In your home

network, they will have numbers like 192.168.0.1 or 10.121.0.1.

Focus your numbering scheme starting at the router. Consider that device the centralhub by imagining a star with rays coming out. The router is at the center and eachcable or radio beam is a ray. The endpoints are where your connected devices willbe. If the router is assigned a number such as 192.168.0.1 then computers, printersand other devices on the network may have numbers like 192.168.0.2, 192.168.0.3,etc. Never assign the same number to two different devices.

For specific instructions on how to assign these addresses, youll need to read thedirections for your router and your computer. Each one is different.

Setting Up and Using a Shared Printer

One of the reasons many home network builders go through theexpense and effort in the first place is to share a printer. Ifsomeone splurges several hundred to several thousand dollars

for a color laser printer, they dont want to shell out that moneyfor each computer in the home. Fortunately, sharing a printer ina Windows-based home network is easy. It isnt much moredifficult in Linux.

There are two related steps: setting up hardware and configuringsoftware.

Whether wireless or cabled, the hardware connections need to be established first.


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The hardware set up is generally very straightforward. There are two ways to goabout it. Either the printer is attached locally to one computer on the network, or ithas a NIC (a network interface card, an adapter) of its own.

In the second case, the printer plugs into the network just as a computer does. It

gets an IP address just as any computer on the network does. In the first case, theprinter doesnt require a separate IP address since its accessed via the computer towhich it is locally attached.

Next, the software configuration has to be done.

First, for a network attached printer, it will need to be assigned an IP address. Selectone in the range associated with your home network. For example, suppose yourmain computer or router is 192.168.0.1 and you have two other computers on thenetwork Jack/192.168.0.2 and Jill/192.168.0.3.

You could select then the next available IP address,192.168.0.4 or skip a few to allow extra numbers for more

computers. It doesnt matter, since all IP addresses areequal, provided theyre in the proper range and dont startwith the gateway address, 192.168.0.1.

The specifics of how to assign the IP address vary fromprinter to printer. Consult the manual. Just ensure that youdont accidentally assign the same IP address twice on your

network. That will invariably cause problems since the router and other systemswont be able to correctly direct traffic on the network.

The following instructions may vary slightly depending on which Windows versionyou are using. For a locally attached printer, all it needs is a name. Use Control

Panel/Printers. Select the printer you want to share. Then, in the tasks pane, clickShare This Printer. Open the Properties dialog box and click on the Sharing tab.Enter a name and click OK. The printer is now shared.

Now that you have a network printer, you can connect to it from all computers onthe network. To add a network printer to your computer, use Control Panel/Printersagain. Click in the tasks pane Add a Printer. Instead of adding a local printer choosefor network printer and browse the network for the right printer.

Be sure to place the printer in some appropriate location. You may want to hide it ina closet to reduce noise, or put it in a hallway for easy access around the house. Or,you may want to centralize your printer, fax, scanner in the home office. Thephysical location makes no difference to the network hardware or software, only the

IP address and/or name is important.


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File Sharing

Once you have a home network established, there are several waysto make use of it. One popular goal is to share files between onecomputer and another without having to use sneaker net, liketrading files by a CD/DVD or, yikes!, by using a floppy disk.

A lot of file swapping goes on via email over the Internet, of course.Thats not technically sneaker net. But its still a roundabout method. Your emailprovider may put a low limit on file attachments, so for larger files you have aproblem. Also, your Internet connection may be (and often is) a lot slower than thelocal speeds obtainable on a home network.

Fortunately, for computers on a Windows-based home network, file sharing is verysimple. In Linux, it isnt much more difficult. Here are two different methods:

If you have a computer with an adapter that shares an

Internet connection, that system is often a kind of hub foryour home network. It often, therefore, serves multiple dutyas a file server. It performs that function in at least twoways: FTP or Shares.

FTP is now decades old, but still a highly useful means ofcopying files from one system to another. One system mustbe an FTP server, the other is the FTP client. Most web servers, for example, haveFTP server software installed. You can use one of the many FTP client softwarepackages available on the Internet. Or, you can use the command line (DOS window)built into Windows.

Click Start/Run, then type cmd into the dialog box (without the quote marks). Typeftp -? (again without quote marks) and it will show you different parameters youcan specify, different ways to execute the command. The differentmethods/parameters are there so you can send/receive to/from different systemsand more.

The other method consists of using something called File Shares.Simple File Sharing is always turned on in Windows XP Homeedition based computers. To turn Simple File Sharing on or off inWindows XP Professional, simply double click My Computer. On theTools menu, click Folder Options. Click the View tab, then select ordeselect the Use Simple File Sharing check box.

You should set the security appropriately for the level of access you want to grant forfolders and files. You can make the files available as Read Only, which preventsanyone from accidentally deleting them. But to transfer files to the other system,you will have to have Write access. To grant complete control, Full Control is thecorrect choice. Right-click a folder, and click Sharing and Security to set theappropriate level.

It can be cumbersome, at first, to go through all the effort of either method whenemailing through the Internet is so simple. And, for occasional file sharing, that may


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well be true. But if you share files regularly, a little time spent learning thesemethods will save you a lot of time over the long run.

Security Issues and Guidelines

Home networks are less expensive and easier to set up than ever.But sometimes the knowledge needed for building them isntaccompanied by guidelines on how to secure them. In some cases,those guidelines are simply ignored. In either case, thats a datadisaster waiting to happen.

Its certainly possible to be paranoid about security. That excessiveconcern is just that, excessive. But a certain amount of caution is wise, not paranoid.Security is like medical insurance. You dont need it often, but when you do youllneed it badly. If you dont have it, the consequences can be severe.

Wireless home networks, which are becoming the more popular option thanks totheir flexibility and lowered costs, are particularly prone to security issues. In theory,and often in practice, someone with a wireless-enabled laptop can simply drive byyour home and tap into your network.

If all they do is steal a little bit of bandwidth thats not much of a problem. But ifthey happen to be clever and malicious, they can now more easily implant a virusinto systems on your home network without your knowledge.

Internet use has similar risks, but in that case you typicallyhave to download an attachment from someone you dontknow to get infected. Thats easy to avoid. But in the case ofa wireless home network, no action is required on your partto get infected. Even if youre following good Internet filesharing practices, you are still vulnerable.

Even in a cabled network, its possible of course, for someoneto break in while youre away. Most such incidents will revolvearound stealing property. But computer infection is one wayfor a disgruntled employee, a party to a lawsuit or otherangry person to take revenge undetected.

In either type of network, the solution is essentially the same. Practice the samegood habits you use for Internet data sharing and amplify them.

Make sure every computer on the network has a password that is required in orderto access the system. Leaving a system unprotected to save a few seconds ofinconvenience at home exposes your whole network to unnecessary risk.

Always change the password on your router. The defaults for most popular vendorsproducts (often the same from one to another) are known by just about everyonewith the skills to do harm. Make it harder for them to do damage by this simple step.


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Configure wireless routers according to the manufacturersinstructions, in order to prevent unauthorized access. All wirelessrouters today use WAP (Wireless Authentication Protocol) to preventdrive-bys from accessing your system. Use it.

Monitor activity on your network and the systems connected to it.

Dont allow friends of your children, neighbors and others to use your network untilyou know them well. The computer knowledge of most teenagers would astoundmost adults today. Most are well meaning, but some havent yet learned how to usea home network in a secure way.

Treat your home network much the same way you treat your credit cards. Dontprovide physical access or pass out information to anyone that you dont want tohave access to it. Its often a short step away from giving them access to yourmoney. Its an even shorter step to your valuable data.

FirewallsIn building construction, a firewall is a physical barrier to help prevent the spread ofa fire from one room to another. The home network equivalent is well named. Thesoftware and/or hardware that constitutes a firewall makes it more difficult fordangerous programs or unauthorized users to access your system.

Firewall protection has two directions. In some cases, you want to prevent dataand/or programs from leaving your computer. This helps prevent any virus youcontract from spreading to other systems on the network or the Internet. In themore usual case, your firewall is configured to prevent unauthorized programs andvisitors from accessing your system from the outside.

That unauthorized access can come from different sources, typicallythe Internet, but also other machines on your home network. A drive-by hacker with a wireless enabled laptop, for example, can access yournetwork and implant a virus. Blocking certain types of access canmake his job harder, even though his system is temporarily insideyour network.

But blocking all types of traffic from all sources in both directions would defeat thepurpose of having a network at all. So, network security always strives for acompromise between locking out and opening up. Where to strike that balance issometimes a gray area.

However, there is a fairly standard list of items that anyone will want to focus on.Keep in mind, the two most common protocols used: TCP and UDP. TCP is bi-directional, UDP is a broadcast that doesnt require a two way connection. Though,UDP traffic can travel in either direction, such as when you ping. Opening up a porton your firewall often involves specifying both the number and the protocol.

The default idea should be to close anything you dont know you will need. Thismeans only open a port or protocol in the direction you need and only once youresure you need it. The default should be closed in both directions.


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HTTP - This is the protocol used for all standard Internet data requests, whethersending (uploading, for example) or receiving (such as accessing a web page).Configure your firewall to leave open Port 80. For secure transactions that useHTTPS, such as many banking sites, open Port 443. 8080 is also often used.

FTP - Many people still use FTP to transfer files to and from computers over thenetwork. That requires opening Port 20.

SMTP - Most email programs use SMTP to send and receive emails. Thus, open Port25 to allow this function to operate.

POP3 - POP3 is also part of many email functions, so open Port 110 for incomingtraffic.

DNS - In order to translate names to IP addresses, DNS has to be able to send andreceive packets. That requires opening Port 53 for traffic in both directions.

DHCP - For Internet access in which your IP address is dynamically assigned and if

you use this feature in your home network, open Port 68.

DOOM - The popular networking game Doom requires Port 666. If you dont play it,dont open it. Remember, the default should always be closed in both directions forany service you dont use.

There are many other standard ports, such as 1433 for Microsoft SQL Server use.Each program should provide documentation about any and all ports it needs, theprotocol used and the direction. Proceed with care.

Troubleshooting a Home Network

Troubleshooting a network can take myriad forms. But mostproblems tend to repeat themselves. The first step is usuallydistinguishing between a software problem and a hardwareproblem. Unless you have specific reasons to question some otheraspect, start troubleshooting by checking the hardware on yournetwork. One of those reasons might be that youve just installedsome new software that affected network settings.

How you do that in detail depends on how your network is arranged. Assume, forsimplicity, that you have three computers connected to a simple hub or switch.

Suppose one computer is connected to the Internet, and uses Internet ConnectionSharing. It will form the focus of the network. Check its IP address, which might looklike 192.168.0.1. This may be the address of the router instead. See the instructionsof your router for details.


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To check an IP address, you can use ControlPanel/Network Connections (Windows XP). But itsa good idea to get used to executing command lineutilities to diagnose network issues. ClickStart/Run, then type cmd into the dialog box,leaving off the quote marks. This opens a DOS

window. Type: ipconfig/all. Youll see the IPaddress and related information.

Next, ping the IP address of the second or thirdcomputer on your network. If you get back Request timed out you have a loss ofconnectivity between the computer executing the ping and the one you are pinging.

Ping from 192.168.0.1 to 192.168.0.2, then from the second to the reverse. Byusing different computers to ping to and from you can often isolate where theproblem is.

Check the lights on the network adapter (NIC or network interface card) on bothcomputers. They should be green and blinking when doing the ping. Check the hub

or switch to which they are attached. The light should be lit continuously. Similarconsiderations apply if you are using a router.

If one of the lights is not lit, check the cables attached to thatport. Its rare, but not too rare, for a cable or connector to gobad. Whats less rare is for a newly attached devices cable orconnector to malfunction. Cables get bent, crimped and subjectto a number of physical stresses that can cause the wires insideto come loose. It only takes one to cause the whole cable to bebad.

Similarly, if you have a wireless network, check the lights on the adapter(s) and the

router. Most routers will come with diagnostic software that will help you trace downthe source of the problem.

For cabled or wired networks, a cable diagnosis meter is a handy device. If you canafford one, something called a sniffer is very handy for either type of network. Withit, you can see packets being passed back and forth and gather other usefulinformation.

If your network is built in sections, the tracert command can be a great adjunct tothe ping utility. It will allow you to gather information about packets as they travelfrom one hop to another. Execute: tracert -? from within a DOS window to get moredetails.

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