Mac + Dollar Sign + WEP = Connection!
I first ran into the Mac dollar sign solution a few years back when trying to connect up to an access point at a campground. Here are the symptoms:
1.) you connect up to a password-protected access point, your Mac asks you for the password;
2.) you type in what you are sure is the correct password, you can’t connect;
3.) you repeat 1 and 2 until sufficently frustrated, then give up.
You are typing in the correct password, it is just that there are two definitions of “password” depending on what type of access point you are connecting to.
Some background…
Older access points use a form of protection known as WEP, which stands for “Wired Equivalent Privacy”. WEP relies on what is known as a key – essentially a “password”, but written in special 16-digit numeral system known as hexadecimal.
What makes it confusing to non-geeks is that hexadecimal uses the letters A, B, C, D, E, F and the numbers 0 – 9 to represent the values. So the hexadecimal string of characters: CABBED1234 looks just like the English string of characters: CABBED1234 to humans. To computers, however, they mean entirely different things.
When Apple designed their WiFi system (Airport and Airport Base Station), they figured that the average user isn’t going to want to remember a string of hexadecimal characters. So the Mac asks the user for a passphrase – something written in English – then does the conversion to hexadecimal behind-the-scenes.
That solution works fine when a Mac is talking to an Airport Base Station. But access points that use WEP and are not made by Apple only deal in hexadecimal. So when administrators set up a “password” on these access points, they are really picking a hexadecimal-base string of characters.
When a Mac connects to a WEP-secured access point, it assumes what you are entering is a passphrase. It does the conversion on it and tries to pass that converted string to the third-party access point. The connection fails, of course, because the hexadecimal-base string of characters that comes out of the conversion process doesn’t match what was set up in the access point by the administrator.
By putting a dollar sign ($) in front of the hexadecimal-base string of characters, you are telling your Mac, “Hey, what I’m entering is hexadecimal already. Don’t convert it.”
For example, say the “password” given to you is:
abcde12345
You’d enter it this way:
$abcde12345
This problem doesn’t occur on access points using the new WPA form of encryption. But there are still enough access points using WEP that you could still run into this problem.
Here is Apple’s official help page on the subject.
So if it ain’t working, put a dollar sign in front of it.