Unable to Check for Update

I had the same problem. After exausting all other means I tried the seeming ridiculous idea of changing the DNS as described here. It worked on both my iPhone4s and my iPad1. My iPhone3s did not have this update issue. This change from a pure networking standpoint should not work and even render the device incapable of resolving any IP address given. On most everyone's home network, their IP address range in usually 192.168.1-255. Any refererence outside that range would be ignored. 8.8.8.8 is outside this range. The DNS entry in this spot tells your phone where it can go to find DNS servers on your network, not the Internet. It is your home router (Airport Extreme or Linksys, etc.) internal address. But for some strange reason everything works as normal no matter what you put there. This should never work. The only thing I can speculate is that something got clobbered during some update or the installation of some app. It could also be that one of the AirPort Extreme (if you are using that) updates broke the system. I never even changed the DSN entry back to the original setting and everything works fine. Impossible conditions exist.

I am extremely curious how the author found this solution as this should never work. My hats off to this individual. Thumbs down to Apple support for not reading this post and trying it.

I'm having this problem on my ipad2 too

Changing the DNS didnt work for me unfortunately

@roger3622 I'm afraid I dont agree with you. From a networking perspective this is perfectly legitimage. Your device will not ignore anything out of its subnet. Instead it will goto the default gateway which will in turn forward the request out to your ISP.

For whatever reason some ISPs DNS servers are not resolving the apple update servers correctly. For me it's SKY Broadband. It's still not working on my home internet, When you tell your device to not use your routers DNS (which will just be forwarding the request to the DHCP'd settings from SKY) annd tell it to go to Google instead (8.8.8.8) it works.

From a networking perspective it is perfectly valid.

@giosdeveloper I'm not sure the issue is as simple as just DNS resolution. Case in point is my iPhone3s did not have this issue. It has the same settings as my other 2 devices, same network settings, everything. I can only speculate that some update or app overwrote something on two of my devices and not the third. I believe you are correct that DNS is the primary issue here but not the only issue. I see with other posts that changing the DNS did not help them.

Hey appreciate your solution post. It ended a lot of frustration for me and others. By the way my network is Mediacom.

Thanks for this post.

My:

iphone4 - wouldn't do the over the air update for a day while at home on wifi, and I noticed the next day at work that it just worked.

ipad2 - wouldn't do over the air update at home on wifi: (error: Unable to check for update) I saw this post, and changed dns locally on the ipad to 8.8.8.8. That change allowed the next over the air update to simply work.

iPod touch 4g (mc544LL) 1 of 2 - same error as the ipad2 when doing the over the air update, repeatedly. Plugged it into itunes via the usb cable and got (error: There was a problem downloading the software for the iPod "XXXXXX". The network connection could not be established.) This post caused me to goto my Airport Extreme router, and change the Internet|Primary DNS Server to 8.8.8.8. After doing that Itunes was able to see and download the update.

iPod touch 4g (mc544LL) 2 of 2 - same as the other iPod.

Thanks for the post, and I hope these details help someone else. One network, 6 Apple products, 3 different symptoms, and 2 different solutions. Ouch!

I have been trying to update like everyone else for the last 4 days with the same error type messages. This morning, Sat. 3/10/12, both of our iPhone 4s, and both iPad 1 devices were updated with USB connection and iTunes to our 2 iMacs. No DNS changes or other complicated changes necessary. Each update took about 5-7 minutes, not the longer times many responses here have commentd on.

What is truly frustrating here is if you go back and look at posts around the December time frame (Mac Rumors and other places) this issue was first discovered in the beta version of 5.1. Now why on earth didn't the OS5 development team look into this is beyond me.

March 7 @ 2pm updated my iPad 2 at doccters office no problem

Got home got error on iPhone 4s and apple tv. Tried everything from rebooting to 8.8.8.8 and 208.67.222.222

Nothing worked on iPhone 4s even went back to doccters office but no go.

On apple tv at home I changed to 8.8.8.8 and it worked just fine. But iPhone 4s it didn't

I restarted phone tried different wifi networks

Finally this morning I got it to work!!!!

Ok not sure if this matters but still has open dns entered 208.67.222.222, 208.67.220.220

But I did that other reset hold down home button and power button until it turns off

Then I turned it back on went into software update and it started updating.

Well it worked for me and haven't read this solution yet.

Good luck

I just used 8.8.8.8 in the DNS and that allowed me to download the update. I have no idea why this is a problem, but I also tried some of the other DNS numbers and they did not work. The software is loading to my iPad2 right now.

Tom

Option 2 worked for me. Thanks!

it is helpful for me resolved problem for my idevices.

Had the same problem with 10.6.8 on an iMac since the Apple announcements. iTunes reporting an update and Software Update taking an age to run and announce no updates. Overriding the DHCP delivered DNS with 8.8.8.8 from my router and it all works. That's showing as the IP address for Google Public DNS and I presume either thay've taken a DNS update correctly or ignored one hence the wide spread and sporadic reports of some being alright with Apple updates or not depending on who your ISP pushes you to by default. Either way thanks for the tip earlier in this post :-) !

I have the same problems too... Did everything but still it can't update...

Still no reasonable answer from Apple after nearly 3 weeks. Does Apple really care whether their products work or not? The answers given here do not make sense; probably the people who were helped by changing DNS settings had originally tried when the servers were busy, or had corrupted DNS caches that were fixed by playing with the DNS settings. I have three iOS devices with identical network settings; on the same network two of them updated immediately, on the first try; the third continues to give the same error after a hundred or so tries at random times over three weeks. None of the "fixes" here works for my third iOS device. The problem is obviously not related to DNS settings, router updates, or anything relating to the network. There is something inherently different about certain iOS devices; Apple is not saying what it is. Apple has had this problem since the developer release in December and still has not fixed it.

Software Updater was patched on the iMac last week and is working normally again, so someone must know something definiely for OSX and presumably the other operating systems ? Though a bit of a Catch 22 if you can't receive the patch in the first place 😉 ! I haven't checked but are there any manual updates around if the DNS change doesn't work ?