When I try to check for upgrade on my iPhone 4 while connected to my WIFI, all I get is a message that says "Unable to check for upgrade. When I try connecting to iTunes for the upgrade, it just sits there waiting for the upgrade software server. Anyone else having this from? Also my iPad2 says that 5.1 is available and when I click on download and install, I get a retry later message after a couple of minutes.
iPhone 4, iOS 5.0.1
Probably because the Apple server is too busy, just keep trying. I was able to update this morning.
I Changed my DNS settings to OpenDNS
On a Mac go to SYSTEM PREFERENCES>NETWORK>ADVACED>DNS
change DNS by adding ( + )
208.67.222.222
then
208.67.220.220
click okay/apply after. then try the update. after the update, just delete the two open DNS server numbers. should revert back to your old one.
That solved the problem for my iphone!...would you happen to have any suggestions for getting the update to work for the Apple TV as well?
Thanks!!! This solved my problem too. In Sweden we seem to have a huge problem for Telia the internet distributor and the Apple server. When I got my MacBookPro last summer my emails disappeard for that readon. But even today when serveral people couldn´t upgrade their iphones they denied!
But ... my phone number vanished from itunes.
Thanks Springbk, my iPhone is updating now as I write this.
Thanks! After over 6 hours of trying to update yesterday, this was so simple.
Any idea what to do on a Windows machine to change DNS?
I, too, was having this problem. Techstures response allowed me to update both my iPad 2 and iPhone 4S. Thanks!
Thank you sir
No, thats not the case. Apple servers have handled much greater peaks in traffic. For whatever unknown reason, Apple servers seem to be blocking DNS servers from IP DNS addresses all over he globe.
THX, that was my problem as well!!
Can i just delet my DNS after?
Yes, but be aware this might be an ongoing issue with the Apple servers. We don't know whats going on there.
For Windows machine
You need to get into your TCP/IP Settings; I have the entire process here, but you need just the DNS server change (number 6). This is very simple and a easy change as I use specific ones when I am on public IP addresses for my Windows machines and my Macs.
, clicking Control Panel, clicking Network and Internet, clicking Network and Sharing Center, and then clicking Manage network connections. 
If you are prompted for an administrator password or confirmation, type the password or provide confirmation. To obtain IP settings automatically, click Obtain an IP address automatically, and then click OK.
To obtain IP settings automatically, click Obtain an IPv6 address automatically, and then click OK.
To obtain a DNS server address automatically, click Obtain DNS server address automatically, and then click OK.
For the AppleTV
Two options:
AppleTV option, you can set up a DHCP with DNS server address;
To configure your Apple TV to use DHCP, from the main menu, go to Settings > General > Network > Configure TCP/IP. In the Network Setup page, select the "Automatically" option.
Router option, What router are you using? You can specifiy DNS server's in your router then change back to your default after.
For anyone wanting to test the speed of their DNS server and which open source ones would be better, you can use a program called Namebench. You might find that your ISP's DNS server is located in a remote location from where you are and a closer one may be available, making your internet browsing faster and more secure with OpenDNS for example.The only downside is that I have found corporate and some public networks do not allow for custom DNS servers to be used on their networks, a simple removal of them will fix that.
Don't be so quick to upgrade, version is very unstable
Cannot upgrade to OS 5.1
