If you search this section of the forum, you'll see several threads on this wifi issue, starting with the 3.0 firmware upgrade.
There seem to be many variables involved in this issue, from the type of device (iPod Touch, various iPhone models), to the type of home router you may be using, to the country in which you are located.
Nevertheless, Apple has put out a tech bulletin for troubleshooting the problem, which seems to be working as a solution for several posters. I'd recommend you try going through the steps in the tech bulletin to try to resolve your issue first.
If you tried all the steps in Apples tech bulletin (
http://support.apple.com/kb/TS1559 )and still no joy, try rebooting your router (unplug the powercord, wait 10 seconds, replug the power cord). This has worked for some posters.
One poster, in another thread, had a Netgear router. He checked to see if the router had a firmware upgrade and it did, which included a specific fix for the iPhone wifi connection issue. Once he installed the new Netgear firmware, problem solved! So you may want to check to see if your router has the latest firmware, and if not, upgrade to the latest version.
You could also try the steps in megauser's post above:
"I, like many others, have been having this "unable to join network" problem. I read multiple, multiple forums and in the end what worked for me was:
(First of all, to do all of this I went to "http://gateway.2wire.net/" to access my router, I have at&t so your access to your router may be different. I did the general steps as in "#)" and the steps I took specifically for att uverse as in "#)*")
1) Changing my Wi-fi network's SSID from the factory name (it was 2WIRE481) to a custome name.
1)* For steps 1 and 2, I went to
http://gateway.2wire.net/, then to "Home Network", then to "Wireless Settings", I was then able to change the SSID and network password.
2) I changed the password of my wi-fi address (I don't think this is necessary, but it was more convenient for me anyways)
2)* Same steps as in step 1. Make sure to click save, otherwise the network will not change it.
3) I completely restarted my network system.
3)*I did this by going to "http://gateway.2wire.net/" and clicking system, then looked at my wireless router and clicked "view details", then clicked "restart the system".
After doing these steps I was able to connect to the network on my itouch by opening wifi and typing in the password! I wasn't able to use my wi-fi for months and this finally fixed it. Thanks for everyone's help."
If still no joy, try switching channels on your router and/or switching from g/b to b only. That worked for a recent poster here.
http://discussions.apple.com/thread.jspa?threadID=2345332&tstart=0htt
If still no joy, you could try to rollback your firmware to an earlier version.
Just Google "iPhone firmware" and you should get several sites you can pick from to download various firmware versions earlier than 3.1.3.
Save those to a separate file you set up for them.
If you try this, and have a problem loading the earlier fw, for Windows users, "Shift click" on the "Restore" button in iTunes and navigate to the folder into which you put your downloaded fw file.
For my iPhone 2g, starting at the oldest, I tried to (iPhone would not allow 2.2.1 to be installed) or did install each fw version. Nothing worked until I got to 3.1.
BINGO!
I did turn ON bluetooth and then reentered my WPA code for my home wifi router (remember this is different than you standard password)and suddenly, not only was I detecting the home net (which I could do with all other fw installs including 3.1.3, but just could not connect), but got a quick and smooth connection. It has been working fine now for a month. Solid, stable, good strong signal, quick connection and at fairly long distances from the wifi hotspot or my home router.
These solutions probably won't work for everyone, but they have worked for many.
I hope it may help you.
Message was edited by: SWFIII
Message was edited by: SWFIII
