If you happen to be in Berlin, you can get 30 minutes of free WiFi in quite a lot of places from a KabelDeutschland™ HotSpot. Unfortunately, each connecting device gets only 30 minutes of free internet per day. On a completely unrelated note, I will talk about changing the MAC address of your WiFi card in Windows 7. I must, again, emphasize the fact that these two topics are in no way related.
# How to change the MAC
* Do an

`ipconfig /all`

and find the description of your WiFi card's adapter.
* Go to `HKEY_LOCAL_MACHINE`

→ `\SYSTEM`

→ `\CurrentControlSet`

→ `\Control`

→ `\Class`

→ `\{4D36E972-E325-11CE-BFC1-08002BE10318}`

as an administrator and navigate to the subkey whose `DriverDesc`

matches this description.
* Change the entry `NetworkAddress`

to the desired MAC address. It's supposed to be a string value of exactly 12 hexadecimal digits, no spaces or dashes. If the key does not exist, simply create it.
* Disable and re-enable your network adapter.
Alternatively, you can download the MAC Address Changer from CodeProject, which is open source and performs *exactly*the above procedure, but with a nice GUI. # That all? No. Of course not. I was changing my MAC back and forth and the adapter just kept switching back to the original MAC, until I finally figured out the problem. In Windows 7, if the MAC of a WiFi adapter is of the form`XY-XX-XX-XX-XX-XX`

, then `X`

may be any hexadecimal digit. However, the lower two bits of `Y`

have a special meaning. Write `Y=[abcd]`

, i.e. `a`

to `d`

are the binary digits of `Y`

. Then,
\[
d = \left\{ \begin{array}{ccl}
0 &;& \text{Unicast} \\
1 &;& \text{Multicast}
\end{array}\right.
\qquad
c = \left\{ \begin{array}{ccl}
0 &;& \text{globally assigned MAC} \\
1 &;& \text{locally administered}
\end{array}\right.
\]
We want our adapter to be unicast and locally administered. So we're left with the four choices `2`

, `6`

, `A`

and `E`

for `Y`

.
# So now that's all?
Yea that's all. Enjoy Berlin!
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