Happy 802.11 day! This tip is for Windows Vista, 2008 RTM, 2008 R2 and 7.
If you work on a laptop, you will have undoubtedly run into the following scenario. You try to connect to the work WiFi network, only to find that you cannot get connected, but other people are connected only feet away. So then you pick up your laptop and walk around the area looking for a connection and at some point, voila! You magically connect to the network. What is going on?
To connect to a WiFi network in Windows 7 you look for the ‘bars’ down in the right-hand side of the taskbar, in the system tray.
Clicking on the bars will open the VAN, or View Available Networks window. This is where you will see the different wireless networks and other networks available to connect to. Names of networks and address are changed to protect the innocent. ;)
As with most big WiFi networks, one access point, or router is not enough to cover all of the area; so many access points are used and your computer connects to the one it thinks has the best signal. In the screenshot above though, it looks like one network, ‘Big Hotel Chain’. Really, behind the scenes, there are many radio signals that my computer could connect to. You can view these other access points from the Command Prompt and using the following command.
Netsh WLAN show all
This is a Network shell command to view all wireless LAN information on your computer. For more information on Net Shell see the following Technet article; http://technet.microsoft.com/en-us/library/cc725935(WS.10).aspx.
The output of the command will be long, longer than the command window size and even may be longer than the command prompt buffer size, so you scroll up and do not see all of the output, use the steps here to configure your command prompt screen buffer size to a larger number; http://technet.microsoft.com/en-us/library/bb491037.aspx. I use 9999 as my buffer size personally.
The output of the command will start off showing you the vendor name, driver, driver version and date of your WiFi adapter along with the supported security modes like WEP40/104, WPA and WPA2. Oops, looks like I may want to update my driver. ;)
After the vendor and driver information is the connection information, which shows the service set identification (SSID) of the network you are connected with the current signal strength and the basic service set identification (BSSID). For way too much information on what these are see the IEEE standards; http://standards.ieee.org/about/get/802/802.11.html. Just remember for now that the BSSID is important if you want to know which access point you are connected to.
Next, you will see possibly some wireless profile information that is not important to this tip, but can provide more insight into what networks you have connected to and saved in the past and networks that any domain administrators have added to your machine via Group Policy (GPO). At the end of the output you will see the available networks.
You can see that there are 2 wireless networks in the range of my laptop; Big Hotel Chain and a blank network. The blank network, SSID 2 is a network that is not broadcasting its SSID over the air and shows up as ‘Other Network’ in the VAN. The first network is the hotel wireless that I am connected to. If you look at the two screenshots above you should be able to match the BSSID of my connection in blue to the available network in blue in the other screenshot. This is the actual access point I am connect to. With this information I can ask others around me to let me know what access point they are connected to and figure out if my laptop is trying to connect to another access point. If my computer always tries to connect to the same access point and has issues, then there could be a problem with that particular access point and I can open a help desk ticket with the networking folks to take care of it and I can even let them know exactly which access point is having a problem. This is sure to have them scratching their heads on how you figured this out.
This helped me out a lot. One note: Instead of changing buffer size, they could send the output to a text file, then open it in notepad:
Netsh WLAN show all >out.txt