I'm having the exact same problem but I don't think it's related the WiFi issue that this thread is about. I have co-workers on iOS (various versions) and Android who cannot connect to our Lync server while on the corporate WiFi but are able to connect just fine from other WiFi networks (home) and on 3/4G.
I spoke to our IT department who are aware of the problem, understand why it's happening but just haven't had the time to fix it yet. I'll ask what the exact issue is. The workaround for me when I'm in my office building is to use our guest WiFi network which is outside of the corporate network. It's not ideal but it works until they fix it.
Sorry if I was unclear - my point in my message was that this was further proof that the phone disables wifi when it is asleep.
Our IT group is also aware of the issues with Lync, and so the behaviour as I am describing is expected (works on Cell and external wifi, but not on internal wifi).
The behaviour highlighted that since the Lync message was received while the phone was sleeping, it proves that my phone was using my cell network while asleep for anything else being sent to the phone and not wifi. I only brought this up because I was noticing significantly more data consumption on the iPhone than on my previous android. (now - there are likely other factors here... LTE capability, first month with new toy, excessive YouTube relating to a local radio contest, etc). But the excessive data usage caught my eye, and made me think more about the LTE-Wifi switch I see when it comes out of sleep mode.
Looks like 6.0.1 is out today. The release notes mention something about WPA2 but says just for iPhone 5 and 5th gen iPod touch. I haven't had a chance to try this yet so I'm wondering if anyone else has.
The update delivers:
- Fixes a bug that prevents iPhone 5 from installing software updates wirelessly over the air
- Fixes a bug where horizontal lines may be displayed across the keyboard
- Fixes an issue that could cause camera flash to not go off
- Improves reliability of iPhone 5 and iPod touch (5th generation) when connected to encrypted WPA2 Wi-Fi networks
- Resolves an issue that prevents iPhone from using the cellular network in some instances
- Consolidated the Use Cellular Data switch for iTunes Match
- Fixes a Passcode Lock bug which sometimes allowed access to Passbook pass details from lock screen
- Fixes a bug affecting Exchange meetings
Same problem here on iPhone 4S with iOS 6.0.1
I have tried the three steps mentioned a few pages ago (forget WiFi network, reboot, reset network settings, etc). No result. I've done a test to verify what is going on, and this is the result:
- Connect to WiFi and wait a few minutes before starting ping to iPhone's WiFi IP address
- Ping times out (no connection to WiFi)
- Colleague sends me an iMessage
- Ping continues to time out
- iMessage is received by the iPhone
- A few seconds AFTER the iMessage is received, ping starts responding
This proves to me that
a) the iPhone does turn WiFi off when in sleep mode
b) the iPhone does NOT reconnect to WiFi to receive data but uses the cellular network instead
WPA2 encryption on the WiFi network, so it might have something to do with that. I don't have a WPA secured network available, but I do wonder if that solves the problem. It shouldn't matter however, it should just work...
After completely erasing my 4s and upgrading to 6.0.1 via itunes restore option I did a similar test as Dominique_v with the difference that I disabled cellular data before and sent an e-mail instead of iMessage; so here is my result:
- Disable cellular data
- Connect to WiFi (WPA2) and wait a few minutes before starting ping to iPhone's WiFi IP address
- Ping times out (no connection to WiFi ??)
- Colleague sends me an e-mail (pushed by Exchange to the phone)
- Ping continues to time out
- e-mail is received by the iPhone (although no 3G/Cellular connection)
- A few seconds AFTER the e-mail is received, ping starts responding (phone wakes up to show incoming mail message)
This proves to me that
a) the iPhone does not respond to ping when in sleep mode, but WiFi is still active
b) the iPhone is connected to WiFi to receive data and does not use the cellular network
BTW: When phone is in sleep mode and I wake it with home button the WiFi icon is not immdiately shown. It takes half a second, then it appears. Anyhow, it seems to be connected to WiFi constantly.
I posted earlier about problems with my iPhone, and I've found some more info:
When in standby, it DOES use 3G to get incoming mails (confirmed by data I got from my carrier, my iPhone received data over 3G during the night). During this time, it was well within range of my WiFi network, but the iPhone did NOT use it during standby.
The problem with my iPad 2 (WiFi only) is worse: because there is no 3G, it does NOT receive mail at all while in sleep mode !!! All mails come in when I wake it from sleep. This is completely useless and renders my iPad somewhat obsolete for general e-mail usage...
I do hope there is a fix for this. And I sincerely hope Apple is looking into this so it can be solved with the next iOS update.
Edit: I filed a bug report for this. I suggest other users experiencing this issue should do the same so Apple is aware of the impact.
Just to be sure for your iPad 2, Dominique:
You mention that mails come in after you wake the iPad. Did you enable the mail notification in lock screen option? If this is disabled it might be that all mails will be received during sleep, but you will not be notified.
Did you try to call the iPad with FaceTime? Keep it in sleep and check if it can be called with another iPhone. What happens?
IOS 6.01 on 4GS.
did the following:
- disable cellular data
- disable 3G
Ping from outside runs a few minutes in sleep mode (2 minutes), then stops.
strange: emails, whatsapp are working, other applications won't.
When it comes back, ping starts again, switching then the display off means ping stops after 30 sec.
Annoying: I run SIP-phone 3CX that stops and is useless then.
I guess only a few apps are running under strange conditions, apple may know.
Lets hope for 6.0.2..
while it is charging, outside pings don't stop, but SIP phone 3CX stops after a few minutes.
That means it is depends on the app with some values - kind of priority:
1 - never sleep (mail, whatsapp, ..)
2 - goto sleep in charging mode (e.g. SIP)
3 - goto sleep in battery mode (e.g. ping answering, SIP)
The only thing that's strange is that you have an app that is probably buggy, that doesn't work when the phone is asleep and plugged in.
Everything else you describe is by design. WiFi shuts off when the phone is asleep, unless it is plugged in. This is to preserve battery, because WiFi uses power continuously when connected, and if it stayed on the battery would run down in a few hours. Apps that run in background can wake it it to send or receive updates. All apps can receive notifications via cellular data, then wake WiFi to get updates.