Wireless Home Network Basics
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Wireless Home Network Basics attempts to be a guide to setting up a basic Wireless LAN (Local Area Network) at home plus some security to keep it in place...
This guide is meant for the intermediate computer user who may not understand many of the terms associated with the field, but has a solid, basic understanding of computer use and terms.
Contents |
[edit] Considerations and foreword
- This text should be read through in its entirety first, this is of CRITICAL importance for security and purchasing. Once done though, parts can be selectively re-read without a loss of understanding.
- Most statistics, such as speed and distance, are the theoretical maximums. Much more so than with hard-wired networks, adverse conditions can SEVERELY reduce these.
[edit] Introduction
A wireless network (Also wireless LAN or WLAN) is a computer network operating by certain frequencies of radio waves. When installed correctly, no difference from a normal wired network should be obvious (Other than the obvious lack of cables).
These are generally used in a home environment for two main reasons: To share printers between them and to share an Internet connection. Normally, networks are created by hooking computers together with network cables and a router (or hub/switch). Wireless networks use various frequency radio waves to do this.
[edit] Common reasons for using a wireless network (in preference to a wired one)
- The most obvious and commonly advertized difference in a wireless network is the lack of network cabling.
- This is especially usefull if the network is a new one being planned and/or where the lengths of cabling would be ridiculously long.
- If the devices on the network are moveable or move frequently, the lack of a network cable may be useful.
[edit] Downsides
- Current standards of wireless networks have lower bandwidths (Speeds) than wired networks. This may be improved in future standards. Note, however, that common home network usage (Viewing webpages, Emailing, printing, etc) will rarely use the maximum bandwidth of any network. Unless you do a lot of intensive file sharing (such as video sharing), this won't be a problem.
- If improperly or poorly set up, anyone within receiving range can do anything on your network without you knowing.
- Since radio waves are an electromagnetic emission, they decrease in strength over distance. If you have a widely scattered network, those on at the very edge of the signal's range may experience very poor speed and reliability. This can be remedied.
[edit] Standards
Far more noteworthy than wired networks, the type or standard of wireless networks is vitally important. If two different standards are used, the network's speed will be adversely impacted at best.
[edit] Different network standards
Currently there are two dominant standards for wireless connectivity:
- 802.11b (Frequently referred to as "b") was the original standard of wireless networking. It supports speeds of up to 11Mbps. It has a theoretical indoor range of about 38 meters
- 802.11g (Frequently referred to as "g") is the newer and current standard for wireless networking. It supports speeds of up to 54Mbps (with standard equipment). It also has a theoretical indoor range of about 38 meters
Note that the letters are never capitalized, even when alone (EG. "I bought a g network card, but only have a b router", not "I bought a G network card, but only have a B router").
Non-standard "extensions" exist which will give speeds in the 108 to 125 mbps range. These will usually only work with other devices from the same brand, that is if you buy an enhanced performance router from manufacturer X, it will not work at 108mbps high speeds with enhanced performance Y or Z cards. However, a device marked as being compatible with 802.11b or g will be able to work with all others similarly marked: any proprietary extensions shouldn't effect basic functionality (That is, the aforementioned "enhanced" devices should all communicate with each other with either b or g).
Because of both the speed difference, its more recent appearance, and other technical reasons, 802.11g is recommended for any new installations.
If, however, you have both b and g equipment, 802.11g is "backwards compatible". This means that an 802.11g device can see and connect to an 802.11b device or network. The downside is that it does so by acting like a "b" device, including the 11mbps speed.
This can lead to trouble if a small minority of devices are B type in a G network. Take the following scenario:
A network with a G router, and two G network cards in computers. When a machine with a B card is brought in and connected, the router will sense this and (Unless set up to not do this) downgrade itself to B class to talk to this newcomer. The two others on the network will also have to follow suit if they are to talk to the router (Which they have to remain on the network). In effect, the B device has "dragged down" the rest of the network.
[edit] "N"
Currently the organization that publishes and designs these standards, w:IEEE, is in the process of coming up with another new one: 802.11n. This is still in development, but is public and the most recent versions are complete enough that they can be used. Manufacturers have been producing "draft-N" devices to take advantage of this. You may want to consider, however, that there is a chance that "draft-N" wireless devices may not be compatible with the completed standard once it is finished. There are several advantages to wireless n as opposed to the old 802.11b/g standards. Advantages include:
- increased range (theoretical range of 70 meters indoors)
- increased speeds of up to 248 Mbps
- supports multiple antennae, or MIMO which allows for faster speeds
- some routers will support dual band, which again, allows for faster speeds
[edit] Security standards
There are three formal standards for securing a wireless network from unwanted access and use:
- Wired equivalent privacy/WEP — Notoriously insecure, AVOID
- Wi-Fi Protected Access/WPA — Newer and much safer
- IEEE 802.11i-2004/WPA2/WPA2-PSK — The latest and most secure of the three
All equipment will state on the packaging which standard(s) it supports. Most modern equipment will support all three. As noted above, equipment supporting only WEP should be avoided as that standard has been fatally compromised and can be defeated with minimal effort by an attacker(with the right tools, this can be done in 2 minutes).
More so then with connectivity standards, the security standard (and password) used must be constant throughout the network. See the "Security" section for more information.
[edit] Components
Wireless networks require hardware, and to a lesser degree, software.
[edit] Hardware
At a minimum, the following are needed:
- A router — This typically connects to a high-speed internet connection and manages the network's communication with the Internet. If you're dealing with a network not connected to the Internet (Rare), a switch or hub may be used. If you're only connecting two computers to each other (An "Ad Hoc" network), only adapters are needed.
- Adapters for each machine on the network — These will be expansion cards for desktop computer and PCMCIA cards for laptops.
If you have a large area to cover, separate antennas and/or access points may be needed.
[edit] Software
All computers on the network need to have an operating system version (Windows, Mac OS, Linux, etc) that can deal with wireless networking.
- All Windows from 98 on have some degree of ability in this field. 98, ME and 2000 require additional software and drivers. XP with the latest updates from Microsoft will work automatically with many network cards, Vista will work natively.
- Mac OS 9 has some wireless networking ability, 10 will work natively.
- Most recent Linux kernels have built-in wireless networking capability.
[edit] Notes
Most wireless routers also have 4 Ethernet (Hardwired, conventional networking) ports on them. If you have a machine that you don't or can't put on the new network, consider locating it and the router close together so it can get on the network by a cable.
Both adapters, routers and other ancillary parts can range in price from 20 USD up to several hundred. A good advice is to go with a well known brand, the currently dominant three are D-link, Linksys and Netgear.
[edit] Hardware setup
Assuming a basic router-and-clients setup, the following hardware will be needed:
- At least one router
- A wireless adapter for each machine that doesn't already have one (Some laptops have built in antennas)
- A cable and adapter for each machine that will be wired into the network
- Depending on the layout of your house and devices, you may need some repeaters. The following section will explain this.
[edit] Location of equipment
Most likely your router will have to connect to your modem (If you don't have an Internet connection, you can disregard this). If this is in a central location for your planned uses, then you will likely not need anything beyond the router and adapters. If you're installing the modem and are planning to have wireless networking, consider installing it in a central location.
If not, you can run more wiring in your house to get it to the router, or accept a weaker signal in the parts of the house farther from the router. If this is an issue, you may want to invest in a repeater that can bring your wireless signal to the far corners of your house.
As discussed previously, wireless signal strength is of significant importance. Some points of information about signals and permeability:
- Wireless signals can pass through drywall relatively easily, but if it must pass through a significant number of walls the signal will degrade rapidly.
- Wireless signals do not travel well through cinder block walls.
- Wireless signals can be disrupted by ducts of a climate control system.
- Water can greatly distort wireless signals. Take into account aquariums, sinks, and water pipes. Remember, the human body is 66% water, so locations with a high density of people can distort wireless signals. This also includes rain or humidity, so consider bath/shower rooms or other regularly wet areas.
If you want coverage outdoors (which can be very nice during good weather with a laptop!), consider locating the router or a repeater near a window facing the direction you want to cover. An upper floor can be an excellent place for a router or signal propagator for coverage around the outside of the building, and possibly inside as well.
[edit] Wiring up the router
Most residential routers were fairly simple to set up and have standardized markings. The usual setup is this:
- Plug the Ethernet (data) cable from your cable or DSL modem into the "WAN" port (If your modem has USB and Ethernet ports, use the Ethernet port and don't connect anything to the USB port).
- Plug any computers you wish to hard-wire to your router to one of the "LAN" ports. If every computer is to connect wirelessly, skip this step.
- If possible, disconnect the antenna, or shield it from transmission.
- Shut off/unplug your modem for about 15 seconds
- Restore power to your modem
- Plug in your router
After a few seconds (At most), the router should start up with the default settings. Leave the antenna disconnected/blocked until you've had a chance to change the wireless security settings, as router defaults are notoriously insecure.
[edit] Router Configuration
- Note that you should read and follow the instructions in the firmware update section first, so you don't have to do this twice
The vast majority of residential routers are configured by a "web-based interface" (A webpage which you can view with Firefox or IE or whatever you use to surf the web).
To access this webpage, a special address (called an IP adress) is used. This is normally detailed in the users manual or "quick start guide". The username and password to be used are also listed. If a "quick start wizard" comes up, you can follow it through or dismiss it. The rest of this guide assumes that it didn't appear or was dismissed.
Once logged in to the router, the first steps should be to strengthen the security. See below...
Expansion cards should be installed with the computer turned off. PCMCIA cards for laptops can be inserted at any time. If the operating system doesn't automatically detect and set up the new networking hardware, try using the disc that came with it.
[edit] Security
Security is of the utmost importance for many reasons. You might be sanctioned or disconnected by your ISP if someone else perpetrates a Terms of service-violation while abusing your connection. Worse, you might get hit with legal action for the same reason. If your Internet connection rate is determined by your level of use, you could easily end up paying a significant amount for it. As the operator of your end of a connection, you are responsible for preventing its illegal or prescribed (mis)use and exercising due diligence. Also, enough people connecting to your wireless can slow your Internet access down. Perhaps most importantly unsecured wireless also puts your personal information and computer at risk.
Security is of increasing importance in higher density locations where someone's increasingly likely to pick up on your signals.
As mentioned above, routers' default settings are notoriously insecure. Almost every router and installation can be well secured with three steps:
[edit] Update the router's firmware
The firmware is essentially the router's operating system (Windows, Mac OS, etc.) and, like every other operating system, it receives security updates. These and other revisions to the router's software are called "firmware updates" and can be found on the manufacturer's website. Since these both improve security (usually) they are important. Note that these updates frequently reset all changes to the router configuration, they should be applied before configuring your router for the first time.
[edit] Enable decent encryption
Most routers will default to having no encryption, or using WEP. Both are EXTREMELY insecure and should be changed immediately. If you have good equipment, there should be an option to change to WPA or WPA2. If you can, select WPA2, if not WPA. If only WEP is available (Or there's no encryption option!), your router is so insecure is should be returned for a refund or replaced with a better one. WEP is little better than nothing, as the FBI showed, it can be defeated in a few minutes with ease.
WPA and WPA2 depend on a "passphrase" (also known as a Pre Shared Key or PSK). Like any other, its strength depends almost solely on its complexity. Good WPA passphrases should be long compared to other passwords, and extremely confusing. The more nonsensical your passphrase, the better. Actual words are not recommended, unless in a very long sentence. For examples,
f7S9^jeiF9ratt4-esttM8,25.4nZ8s
is more secure than the passphrase
fff4526----354
which is better then
4352354frewch
which is better then
sdfnvuihgwkjsgdf
which is better then
toaster
etc.
For more information on choosing good passwords, visit Password Policy.
Finally, remember you will probably only need to enter this once (When you first set up your network and computers), so you can make it really strong and write it down rather then try and remember it. Just make sure you don't lose the paper, but keep it safe somewhere.
[edit] Change the network name (SSID)
Routers will usually default to giving networks a certain name. Linksys defaults to "linksys", Netgear "NETGEAR" and D-link "default". An unchanged network name is a dead giveaway the network is unconfigured or minimally configured. Since most such networks have no security to them, they are immediate targets for attackers.
Also, if your in an area with many networks, a lot will have the same default as yours. If you don't change it, you might end up connecting to someone else's network without intending to or realizing it.
The new name should be something recognizable, for your sakes, as well as anyone else you may invite to use it.
Another good way to secure your network is to disable "SSID broadcast". This prevents your router from advertising its presence to everyone in the area. Be aware that this does not make your network invisible, it just makes it less likely that it will be stumbled upon by your neighbor or something. Also note that this will require you to manually configure your wireless software (on your computer) to connect to the network, since the software will no longer detect it automatically.
[edit] Change the configuration password
Finally, you should change the password to access the routers web configuration to something other than the default. Entire web sites exist with nothing but default passwords (See, for example, this Google search for "default router passwords". If a person made use of these unnoticed, they could disable all security measures and take over your network (along with steal your personal information). Follow the guidelines in the Password section in order to improve security.
[edit] Change remote access setting
Most routers have an option to allow remote access to the router, allowing anyone on the web to potentially break into your network and change settings. Unless you have a need to regularly configure your router when not physically on your network, this should ALWAYS be disabled.
[edit] Try it out
Once the cards, router and modem are set up and in action, see if you can connect to the Internet from a wireless and (If there is one) a wired-in computer. Everything should work the same as it had in the past.
