No internet access over wifi (the infamous “local access only” problem)
On my Windows laptop, wifi connnects easily to all wireless routers, but every once in awhile it will not allow connections all the way out to the internet. This mainly seems to happen when I switch to a new environment, such as bringing my laptop out of the home and out to a coffee shop. This first started happening to me in Vista, and the problem has persisted in Windows 7 Pro.
The problem, which you can verify by opening a command prompt and typing
ipconfig, is that sometimes Windows assigns itself a bizzarro IP address
instead of the one given by the DHCP service on the wifi router. This made-up IP address
is usually on some odd subnet and never of course on the same one as the actual wifi
network.
Here’s the (ugly) solution: Open Notepad and cut/paste in the following:
ipconfig /release
ipconfig /renew
Save it as something like wifi.bat. Save it somewhere permanent but out
of the way, and put a shortcut to it somewhere handy (on your Start menu or
something).
Now when you have the problem, right-click this file/shortcut and click “Run as Administrator”.1 It might take a little while, but five’ll getcha ten your problem will be all cleared up afterwards.