my wifi is unreliable and I don't know why. (os x, dsl)

November 5, 2010 12:11 PM

my two year-old macbook pro recently got a new cousin: a new mbp. both are running 10.6.4. my old mbp never had any problems establishing a wifi connection to my dsl modem, which is protected using wpa2. my new mbp sometimes can't connect via wifi/airport to said dsl modem. I usually get "connection timeout" errors displayed if I manually select the network. this is at the same time as my old mbp sitting right next to it is connected.

I have to send the new mbp to sleep, wake it up again and after doing that two, three times, the connection usually works again. you can imagine how frustrating that is. to top it off, I have the same issue with a brand-new 27" imac that I got my dad last month: his pc sits next to it connecting happily to his (non-apple) dsl modem while the imac frequently requires being sent to sleep and woken up again.

what's going on here? any thoughts on what I might try?

caveats:
-software update says everything is up to date.
-I've spotted many "me, too" problem descriptions on the apple.com discussions site but no solution. it might have evaded me.
-can't leave my network wide open. the kids next door are massive filesharers and they don't exactly hide their activities.
-I can't replace the dsl modems.

posted by krautland to computers & internet (6 answers total)

What brand and model of wireless router do you have? Is the firmware up to date?

(And this is not a fix, but while you're waiting on a real solution, have you tried just turning AirPort off and on from the menu bar instead of putting the machine to sleep multiple times? Might save your sanity in the short term.)
posted by bcwinters at 12:43 PM on November 5, 2010

I can't tell you what dsl box this actually is since my provider brands them with his logo and strips all other information even from the admin panel. the firmware is up to date.

turning airport off and on has worked once but not always. I usually need to wait until it complains that none of my selected networks are available, send it to sleep and wake it back up again.
posted by krautland at 12:54 PM on November 5, 2010

Can you filter by MAC address? (not mac as in apple, but as in media access control). No passwords, and your neighbors can't piggy back. This is a hassle if you have new computers coming into the house regularly, but is quite secure from what I understand.
posted by bessel functions seem unnecessarily complicated at 1:55 PM on November 5, 2010

Filtering by MAC is not secure, as the MAC is sent in the clear and an attacker can fake it:

http://www.maxi-pedia.com/how+to+break+MAC+filtering.

You really need WPA2-PSK with AES and a good password to be fully secure. Anything less isn't going to work against a determined attacker (granted, MAC or WEP might be sufficient against your neighbors, but it's kind of the equivalent of hanging a KEEP OUT sign on the door without really locking it).

But back to the original problem. Just today, we solved this bizarre intermittent wifi problem in the office, where a MBP would occasionally not be able to connect to the router, even though wifi appeared to be working. This affected this and only this laptop.

It turned out that the monitor it was hooked up to for a secondary display caused wifi to die. It's basically exactly this problem:

http://discussions.apple.com/thread.jspa?threadID=2583679&tstart=0

Unplugging the monitor would make everything happy. Plugging the monitor in would make things sad.

Some other discussions suggests that it's an issue with the the video hardware on the MBP running a second display at a particular screen resolution. But your problem could be in places you don't suspect.
posted by chengjih at 2:57 PM on November 5, 2010

I can filter by mac address and I can hide my network from showing up but I don't trust the kids to not find it. I don't have an additional monitor active in here at all, though I can't speak for my neighbors.

hm.
posted by krautland at 11:06 AM on November 6, 2010

Are there a lot of networks near you causing interference with yours? I don't know why but macs seem to have this problem. Try changing the broadcast channel in your router and see if that helps.
posted by chillmost at 5:59 AM on November 25, 2010