Help connecting Airport to Internet
May 2, 2016 6:20 PM Subscribe
Weird situation. I have two Mac computers right next to each other. One recognized the wifi on the Airport and logs in no problem.
The other sees the network but can’t log in.
I’m usually pretty say with these things but no luck resetting airport, running diagnostic tool or rebooting.
I’m stumped. only thing I can think of was I used the utility privacy scan and it might have tossed some Finder cache files.
Any help would be hugely appreciated.
Thanks
Create a new account, try logging in with that one.
Are both computers on the same OS?
Might be helpful to know models and to know which airport. And when you say, "Resetting airport" you mean rebooting or a full factory reset?
posted by cjorgensen at 6:36 PM on May 2, 2016
Are both computers on the same OS?
Might be helpful to know models and to know which airport. And when you say, "Resetting airport" you mean rebooting or a full factory reset?
posted by cjorgensen at 6:36 PM on May 2, 2016
If the non-connecting Mac has "Remembered" the wifi network, tell it to forget it and try again, re-entering the password. It's possible the Mac is trying and retrying a password that you fat-fingered, like hitting redial after calling a wrong number.
Also check the network area of system preferences and make sure the non-connecting Mac is not set for anything like Manual IP or DHCP with Manual IP address or any such thing-- it should be on pure DHCP if you're like most people. If, on the other hand, you are doing static IPs on wifi (an uncommon setup, probably done for specific reasons), then you're probably an advanced user and know what to look for here, but may or may not have looked already.
posted by Sunburnt at 8:16 PM on May 2, 2016 [1 favorite]
Also check the network area of system preferences and make sure the non-connecting Mac is not set for anything like Manual IP or DHCP with Manual IP address or any such thing-- it should be on pure DHCP if you're like most people. If, on the other hand, you are doing static IPs on wifi (an uncommon setup, probably done for specific reasons), then you're probably an advanced user and know what to look for here, but may or may not have looked already.
posted by Sunburnt at 8:16 PM on May 2, 2016 [1 favorite]
Looks like the OS has some built-in facility to deal with this in the particular case of Airport:
System preferences -->network-->Assist me--> A screen with multiple options will appear, asking "How do I connect to the internet", click on the first one," I use Airport to connect to the internet Wirelessly, and click continue. And follow through.
posted by Sunburnt at 8:19 PM on May 2, 2016
System preferences -->network-->Assist me--> A screen with multiple options will appear, asking "How do I connect to the internet", click on the first one," I use Airport to connect to the internet Wirelessly, and click continue. And follow through.
posted by Sunburnt at 8:19 PM on May 2, 2016
Response by poster: It looks like the DHCP can’t find the IP address, even when I renew the lease.
Suggestions?
posted by captainscared at 4:30 AM on May 3, 2016
Suggestions?
posted by captainscared at 4:30 AM on May 3, 2016
I suppose you've checked the security settings in your wireless access point to make sure it hasn't either blacklisted or failed to whitelist your non-working machine's MAC address? Lots of people set up MAC blocking "for security" (even though it offers no useful protection against even moderately competent attackers) and then forget they've done that, only to have it bite them when legitimate new clients need connections.
Other than that, DHCP failure on wifi is usually down to an incorrect wifi passphrase (pre-shared key) and that's usually cured by "forgetting" the particular wifi connection concerned and then reconnecting to it, at which point you will be prompted to re-enter the passphrase.
If the pre-shared key is different on client and WAP then they will see each other's packets but read only gibberish inside them, causing any protocol to fail. There's nothing particularly special about DHCP in this regard: it's just that DHCP is the first packet exchange a wifi client will typically attempt to perform on connection.
posted by flabdablet at 6:46 AM on May 3, 2016
Other than that, DHCP failure on wifi is usually down to an incorrect wifi passphrase (pre-shared key) and that's usually cured by "forgetting" the particular wifi connection concerned and then reconnecting to it, at which point you will be prompted to re-enter the passphrase.
If the pre-shared key is different on client and WAP then they will see each other's packets but read only gibberish inside them, causing any protocol to fail. There's nothing particularly special about DHCP in this regard: it's just that DHCP is the first packet exchange a wifi client will typically attempt to perform on connection.
posted by flabdablet at 6:46 AM on May 3, 2016
Another failure mode involves WPS (Wifi Protected Setup) where instead of explicitly entering the same pre-set passphrase on each new client, you press a button on the WAP to make it and the client negotiate a unique-per-client random passphrase between themselves.
If you then factory-reset your WAP, your client will end up with a stale passphrase. If you've always been using the WAP's default SSID (network name) then the client has no way to discover that its passphrase is now wrong, other than that it can no longer make sense of anything the WAP says to it.
Again, telling the client to forget that connection, then rebuilding it by whatever means you used initially should be enough to get it going.
posted by flabdablet at 7:17 AM on May 3, 2016
If you then factory-reset your WAP, your client will end up with a stale passphrase. If you've always been using the WAP's default SSID (network name) then the client has no way to discover that its passphrase is now wrong, other than that it can no longer make sense of anything the WAP says to it.
Again, telling the client to forget that connection, then rebuilding it by whatever means you used initially should be enough to get it going.
posted by flabdablet at 7:17 AM on May 3, 2016
Oh, and all that renewing the lease does is issue a new DHCP request over the existing connection. It doesn't destroy and re-make the connection itself.
posted by flabdablet at 7:22 AM on May 3, 2016
posted by flabdablet at 7:22 AM on May 3, 2016
To expand on above answers: on Mac OS you "Forget" a network by going to System Preferences > Network, selecting your wireless interface in the left column, clicking "Advanced" in the bottom-right, scrolling through your Preferred Networks: under the Wi-Fi tab, clicking on the network in question, and clicking the [ — ] (minus) button to remove it, confirming in the confirmation sheet, clicking OK to dismiss the Advanced screen, and finally (don't forget this step!) clicking Apply in the bottom-right of the Network pane.
If the above doesn't work or "stick" for some reason, you can also delete saved keys from /Applications/Utilities/Keychain Access. Tread lightly here, some people exacerbate authentication issues real badly by taking a hatchet to Keychain Access which you don't want to do.
Anyways, try that first. If it doesn't do the trick, go again to "Network" and hit the pop-up menu at the top for "Location". A "Location" in this parlance is just a saved group of network settings. So we're able to both not fuck with anything and also get a fresh start, choose "Edit Locations..." then hit the [+] in the corner of the sheet and name your new location "Test" or something. Hit "Done" and it'll be chosen, but you still have to hit "Apply" in the bottom-right of your System Preferences window. This way you're operating with a new, unmolested set of network settings. If this fixes it, I say roll with it. If not, you can roll back by choosing "Automatic" or whatever was originally selected from the "Location" pop-up.
You can also safe-boot the Mac by holding Shift during startup, which prevents third-party kernel extensions from loading. Would be curious if this had an effect (if the previous suggestions didn't).
Not familiar with PrivacyScan myself, but I can imagine an app with admin permission could delete any number of related files that could conceivably have this effect. On the other hand, network issues and especially wireless network issues are among the most inscrutable in all of home computing so sometimes it's just a "shit happens" thing.
Good luck!
posted by churl at 3:08 PM on May 19, 2016
If the above doesn't work or "stick" for some reason, you can also delete saved keys from /Applications/Utilities/Keychain Access. Tread lightly here, some people exacerbate authentication issues real badly by taking a hatchet to Keychain Access which you don't want to do.
Anyways, try that first. If it doesn't do the trick, go again to "Network" and hit the pop-up menu at the top for "Location". A "Location" in this parlance is just a saved group of network settings. So we're able to both not fuck with anything and also get a fresh start, choose "Edit Locations..." then hit the [+] in the corner of the sheet and name your new location "Test" or something. Hit "Done" and it'll be chosen, but you still have to hit "Apply" in the bottom-right of your System Preferences window. This way you're operating with a new, unmolested set of network settings. If this fixes it, I say roll with it. If not, you can roll back by choosing "Automatic" or whatever was originally selected from the "Location" pop-up.
You can also safe-boot the Mac by holding Shift during startup, which prevents third-party kernel extensions from loading. Would be curious if this had an effect (if the previous suggestions didn't).
Not familiar with PrivacyScan myself, but I can imagine an app with admin permission could delete any number of related files that could conceivably have this effect. On the other hand, network issues and especially wireless network issues are among the most inscrutable in all of home computing so sometimes it's just a "shit happens" thing.
Good luck!
posted by churl at 3:08 PM on May 19, 2016
This thread is closed to new comments.
posted by captainscared at 6:22 PM on May 2, 2016