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I've got a Mid-2010 17" MBP freshly upgraded to 10.7. I went to the coffee shop today to do a bit of work, but I was unable to connect to the wifi network. I had been there yesterday(though without my laptop) and the wifi password had been changed. I updated the password on my iPhone and iPad, and those devices have been connecting to the network with no problems.

Today when I went in with my Macbook, however, I was unable to establish a connection with the network. I thought it was a bit strange, since it never told me the password was wrong(keep in mind, the laptop still remembers the old wifi network password), it just grabbed a self assigned IP and complained that it couldn't connect to the internet.

This is what I did in effort to establish a connection, with no success:

  • Removed the network in question from my saved wifi networks. Upon attempting to reconnect nothing changed, still gets a self assigned IP, never asks for a new password, no internet connection.
  • Removed all entries for the network in question from the Keychain. After removing the keychain entry, any time I reconnect to the network, the keychain entry is re-added with the old, incorrect, password.
  • Edited the password in the keychain entry to the new, correct, password. This resulted in the same behavior as my first attempt, nothing new.
  • Removed entry from saved networks, deleted keychain entry, restarted mac. Exactly the same as before.

So after a good 20 minutes of attempting to connect to the network, I could never even get it to prompt me for a new password(the password it has stored is definitely different than the current, correct, password for the network). So I gave up and came home to attempt to figure it all out.

Any suggestions on how to get connected to this network with a new password? Have I done all the right things, and should now just go file a radar on this behavior?

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Be sure to check in system and user keychain when cleaning out passwords. Probably not the issue since you have a link, just not a routable ip address. –  bmike Jul 22 '11 at 1:16
    
@bmike I feel a bit foolish that I didn't follow this advice straight away, but the problem was an entry in the system keychain. I only thought to check my user keychain. If you want to turn this into an answer I'll gladly accept it. –  David Barry Jul 24 '11 at 17:33
    
same problem here –  andy Sep 14 '11 at 11:09
    
I have found that the connection will "connect" but then not be able to communicate, if the network uses WEP and you enter an incorrect password of valid length. In those cases the self-assigned IP a symptom... –  conny Sep 24 '12 at 11:31
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4 Answers 4

up vote 1 down vote accepted

If you have checked both the user keychain and the system keychain for old passwords, we're left with obscure guesses.

Two things come immediately to mind (from the obscure side).

  1. Your mac will join any base station with that SSID. I have seen people literally setting up a second router in busy coffee shops - you have to hold the option key and make note of the mac address you have connected to and see it change to catch this.
  2. If your wifi connects to the router wifi, it doesn't mean the dhcp server has any more addresses to lease. You will need the owner to reset or power cycle the router to see if the leases are all out and unexpired. You basicall have a great pipe connecting you to the main, but no water is flowing to you until you get a lease.

(edited with comments from David Barry - he found the true cause in his case which was an old stored password in the system keychain)

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I was having exactly the same problem at my own coffee shop. Turns out my base station was out of leases. Rebooting the station has got the machine back online. –  Digitalchild Jul 22 '11 at 1:06
    
Once I get know my coffee shop owners, I bet them 4 lbs of beans I can make them and their clients happier with the Internet. In two weeks time I will come to make a purchase or collect my booty. Whether they accept or decline my wager, I help them set the lease time to 15 minutes. I have not lost yet. –  bmike Jul 22 '11 at 1:12
    
Good idea, fixing mine now. –  Digitalchild Jul 22 '11 at 1:20
    
Very good things to consider. I'll have to see if I can get them to power cycle it tomorrow and see if that does the trick. However as I mentioned before, after I couldn't connect with my laptop, I pulled out my phone, and "forgot" the network to force it to re ask for the password and it was able to connect with no issues. If the router was out of leases shouldn't my phone have experienced the same issue? –  David Barry Jul 22 '11 at 4:42
    
Hard to guess - if it had the last reservation, no - your phone would have gotten a routable IP even later than the mac being denied. you'll know to look in prefs tomorrow to see ip details. If the phone gets an ip, you can test by manually assigning the same to your mac and turn off the phone wifi just before applying the change tonthe mac. Your question was so detailed, I assumed you had nailed the obvious and dove into obscure. –  bmike Jul 22 '11 at 4:55
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What a puzzle. You have tried all of the likely issues regarding wifi so perhaps you might rule in or out a couple of other pieces.

I have a few ideas for you to consider.

First find and delete all session cookies, cache and browsing history related to this coffee shop. If it fails in the same way, try to get online with another browser from the same user account. If this approach does not work, here's plan B.

Create a second user account on your mac and try to login. This is a popular approach often recommended by Apple when I have had problems. If that works, we can assume something in your primary user account is getting in the way.

One of the things that could be in play here is the "man in the middle" scheme or something akin to firesheep. I'm not the right person to help with issues like this but you are experiencing an unusual situation. Googling these terms might help.

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I saw your edit, but that should have been made a comment under the answer or comment for the person it was directed towards. Chances are they wouldn't see your query when it is included in your own answer. Adding a comment places a flag in their account as something they should look at. –  Philip Regan Jul 23 '11 at 14:41
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Situation: well-meaning staff will tell their customers to remove and re-join the wireless network in question after a password change, only to have their efforts thwarted by the OSX Network Settings that never bothers deleting the Keychain item associated with a formerly trusted network.

I for one would love it if we could .. Opt-click-join to force the password dialogue, or something, anything would be easier than having to explain the following procedure:

  1. Open Keychain
  2. Make sure you have Login keychain and the All category selected in the left pane
  3. Enter partial network name into the keychain Search field
  4. Select the corresponding found item, delete it, confirm admin password
  5. Disable+Enable wireless network interface
  6. Re-select the network, enter the updated password
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I had the same problem. The answer above did not resolve it, but choosing "Join other Network" and then entering the same network name did work.

A little more detail: I had this problem when Verizon Fios Premium tech support turned off my WEP security on their router in order to diagnose a wireless connection problem with a Win XP laptop. When they turned the security back on with the same password the Air book no longer connected, but if WEP was left turned off it worked ok. So when I chose "Join Other Network" the setting came up as no security. Not sure if that was because I was last connected to the current network with no security.

In any case when I entered the same name of the current network and selected WEP Security it asked for the PW and I'm off and running. Your mileage may vary. HTH. ed

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