This is to all the guys having problem with iphone wifi.
I am not a tech guru so I wont be much technical but this is what i have experienced
To start of with easy understanding, its a fault in the iphone 5, not in IOS6. Sorry guys but the handset you have the sooner you change the better, because this is a hardware issue not a software so do not wait for apple to find a software fix.
Now the issue:
iphones 5 having problem with wifi can connect with WEP, WPA-TKIP settings on your router. But They dont work with WPA-AES. I tried with WPA-auto but mine didnt work, few other people said their iphone not working with WPA- AES strangely worked with WPA-auto!!
This is not an issue at all if your at home becuase you can tweak your settings anytime you like. you can change your settings to WPA -TKIP and it will work perfectly fine. Its a little less secure than WPA-AES but still your iphone5 will work. But this will be a BIGGGGG issue if your trying to connect to the networks you dont own becuase if they have got WPA-AES on then your in trouble.
I am here sat at my office desk but can use their wifi at all. And as i am in ground floor, 3G network is very very poor so when i am at office i say to myself ''i want my iphone 3gs back'' but its too late!!
Luckily i did a lot of research on this and figured out the problem soon so i have asked my carrier to exchange my handset, it should be in its way.
Hopefully this one wont have any issues.
So ask for a replacement handset before your time runs out.