Introduction

This is my page on wireless Lan. I have been using wireless lan for a couple of years now. It has changed a lot over time and has become far more inexpensive. Of course in making it less expensive the designers have made trade offs. Wireless lan today is actually not as good as it was.

Wireless Lan has made great strides in the area useability but it still has a ways to go. If you have the time and patience it can work well for you, but don't think this is a a plug and play world.

b/s Vs B/s

By the way in case you are unaware the nomenclature is b/s is bits per second Vs. B/s which is Bytes per second. The translation is b/s divided by 8 = B/s.

What is wireless lan

With wireless lan (well designed) you can have connectivity coverage around your house, in your yard, on your deck, wherever you want. This includes internet access, access to network printers file shares (gated of course by the speed of your wireless Lan) and the like! It can be amazing.

Security or Lack there of

Ok let's get this out of the way first. Wireless Lan is not secure. There are plenty of tools out there to crack pretty much any kind of default add ons to wireless lan. For the first little while it was believed that the various parameters that make up your wireless lan connection including SSID, and the like would provide some basic security. Ehhh wrong. There are plenty of tools that can sniff these and tell you them all. Windows XP has made great strides in useability of wireless lan and one of the areas it has done is that it has a snoop feature that goes out and detects any wireless connections that might be available. By the way if you do not see a selection for "View Available wireless networks" then the driver you have for your wireless lan card is probably not designed for XP. This seems to show up ONLY when the driver s explicitly coded for XP.

WEP is not a solution either

Some people believed that the solution to wireless security problems is WEP. Ehhhhh wrong again. There are plenty of tools out there on the net that will listen in and "decode" the encryption being used by WEP. WEP is a deterrent and will exclude all but hackers, but none the less it will not fix your problems. By the way this include 40 bit, 64 bit and 128 bit WEP. Since it's free you might as well use it but don't be lured into a false sense of security. By the way there are occasions when turning on WEP will have a dramatic impact (decrease) on the bandwidth of the wireless connection. It has to do with the power of the access point you are using and whether it can keep up with the demands of WEP.

WEP Inter operability issues

While companies advertise inter operability (the ability to work with other companies products) they are not motivated to do so. They would rather you bought two of there cards. WEP works on either a key, or a password called a pass phrase. Problem is the translation between Pass phrase and key is specific to a vendor. So each company does it a little different. So if you are going to use devices from different companies you must be able to enter a key rather than a pass phrase. If all you can enter is a pass phrase then all devices better come from the same company. By the way, be aware that the pass phrase and sometimes the key is stored in the registry unencrypted for hacking programs to help themselves to, furthering the point that WEP security is pathetic.

Range

Some people think oh well you can't really receive my signals unless you are close to my home. Ehhh wrong again, there are high gain antennas that can pick it up miles away.

There must be a solution?

Indeed there is. The only real solution is to encrypt the packets before they ever touch the wireless lan and the easiest way to do this is to use VPN (Virtual Private Networking). VPN will secure your network if you do it right. You need to make sure that the use of the VPN tunnel is mandatory not optional. If it is optional, well the hackers may choose to not use it. (Hmmmm what a surprise these nasty hackers). You can read more about VPN.

Concerns about security

There are really two different sides of security you need to worry about. First is snooping or listening in on your network. With snooping the hacker can get access to your passwords and the like. This means that your security is completely compromised. Of course this depends on the program you are using and whether it does some encryption on it's own. Programs like mail, ftp, telnet all pass the password in unencrypted form.

Second side of security to be worried about is using your lan connection. This would include use of your internet connection for things like hacking on other sites, denial or service attacks and the like.

Different types of Wireless Lan

There are currently three generations of wireless lan cards on the market today with some inter operability. Assume your cards of different vintage will not work together and you may be surprised. The three vintages are: Be aware that wireless lan cards are half duplex meaning that you are either transmitting or receiving, not both.

How to connect your Wireless Lan

Ok now that we have the paranoia out of the way it's time to address how to connect with your wireless device. Now this picture changes depending on if you have both Wired and Wireless networks. In this situation you obviously are going to want to be able to get at the devices on both networks without thinking about which network they are on. This is possible. If all you have is wireless then life is a little more simple.

My network (for reference)

You can connect your wired and wireless worlds in a number of different ways. Each of these has there costs, benefits and limitations. First of all you can choose to spend money on a dedicated device to bridge these two networks. Otherwise you can use a PC to bridge the networks.

You can use a PC to act as a router forwarding IP traffic between the two networks. As a point worth mentioning if you have NETBEUI enabled these packets will not be passed.

NT 4.0

You can easily enable IP forwarding by:

Win2k Pro

In Windows 2000 Pro they have chosen to remove the ability to enable IP forwarding (or really to hide it). You can easily enable it by: Courtesy of NTFAQ.

Win 2k Server

Be aware that Win2k is rather single minded about life. The net of this is that your router can not also be your VPN server and can not also be your Internet Connection Sharing machine. Win2k tends to prefer you have one machine per purpose (with some exceptions).

In all of the above the machine will act as a routing passing IP packets between your wired and wireless networks. I do not find that DHCP packets get passed properly. So you solve this I put the wireless device on fixed IP such as 10.0.0.x. Your wired network assuming it's on private IP will be on 192.168.0.x. I recommend you put the wired adapter in the router on fixed IP. So let's say 192.168.0.254. Last thing you need to do is create a path from your ICS machine (192.168.0.1) and the new wireless network 10.0.0.x. This is pretty simple.

route add 10.0.0.0 mask 255.255.255.0 192.168.0.254 -p The -p says make it a persistent route which means it will stick between reboots. In my network the name server does not properly pass requests. Probably to do with the "light" nature of the DNS in ICS. So I get around this by using LMHOSTS. If you are not aware this allows you to make a fixed translation between a IP address and a name. This file is located in directory C:\WINNT\system32\drivers\etc for NT and 2000. Copy lmhosts.sam to lmhosts. and manually enter the Ip addresses you want translated. This will work for both TCPIP and network shares.

Windows XP

Windows XP has added a very nice feature called network bridging. This works better than simple IP forwarding and will properly pass DHCP requests (removing the need for fixed IP) and DNS (removing the need for LMHOSTS).

Access point

Now for the simpler more elegant solutions. You can buy a device called an Access point. This device will completely pass all DHCP, DNS and packets between the wired and the wireless lan. These devices make the line between wired/wireless invisible. They work well. You can have multiple Access points as needed to give you the coverage you need. As an example of an access point check out Linksys WAP-11. One of the better features of this Access point is that it allows for an external antenna to give better range. A better antenna is a lot cheaper than another access point.

Wireless Lan router

You can also buy one router that will serve both your wired and wireless networks from your cable modem or ADSL. As an example of this checkout Linksys BEFW11P1. Once again this device allows for an external antenna. However I strongly recommend you skip these devices. You will need to place your wireless Access point carefully to get the best coverage. This likely will not be a place where a connection to your cable modem and wired network is available. As such I personally recommend an access point.

Different types of wireless lan cards

You can get a variety of different wireless Lan cards. These can be things like In case you are not aware:

Range

As price has decreased range has too. Trade offs are being made. The 2Mb cards generally had a little better range than the 11Mb and from what I have read 54Mb will be even worse. because the range is limited you will need to play with placement of your access point in different places in your location to get the coverage you are looking for. You can also buy external high gain antennas that can dramatically increase range even to the point of miles. One of the things that will attenuate your signal is water. This includes things like aquarium, wood, etc.

Wireless Modem

Using a program called NPCOMM you can use your TCPIP connection from your wireless LAN to share out a modem and thus get a wireless modem added to your network. This program is a little difficult to get working and I have not been able to get the server to work on Windows 2000.

Other Devices can interfere with your Wireless LAN cards

Wireless Lan cards (802.11 and 802.11B) work on 2.4GHZ. Anything that uses this frequency will interfere with them. This can include your Microwave oven, some cordless phones, some wireless security cameras and the like.

Other links

Practically Networks article on Range Problems.
More on Range at Practically networked
A list of wireless lan products at ProVantage.
External Antenna at HDCOM.
No Wirenets.com
Connecting two Wap-11's 1 Km away
My page on 802.11G
There is also a news group alt.internet.wireless that I have found useful.

Tools

Wireless Lan Expert tool.
Access point sniffer
Net Stumbler
Wardriving
WAP-11 Power ouput hack