Written by 
As many of us are, I was extremely anxious and impatient to download the new Apple operating system. But to my frustration, my download connection continued to timeout at, what seemed to be, the completion of the new firmware download. For the first few days this was a widespread issue due to the overload of pings to the Apple servers. After four days of waiting, and the issue not resolving, I turned to The Google. Turns out there are a few things you can do that will help you with this problem. The following tips can help if you are still having trouble downloading and installing IOS 5.
Plug In
Maybe your wireless internet is being wonky; this eliminates a factor that could lead to a network timeout. This is also a good time to tell your roommate to stop streaming movies for a few minutes.
Temporally Disable Firewall/Antivirus
Firewall and antivirus software can increase the chances of network time-outs by adding an extra filter to the transfer of data. You may want to stop looking at your adult content and pirating movies for a few minutes while your firewall is down.
Clear DNS Cache
Your computer may be storing out-dated or a corrupted cache from an original DNS lookup to the apple servers. By clearing the DNS cache, you can be sure that a fresh connection is being established. Find instructions to do this here.
Thank you! I was having exactly the same problem and this solved it. Also needed to clear some space on my PC Hard Drive for the backup, but I didn’t know that was needed until I got past this timeout problem with your help.
I tried for a week trying to get my phone to update. And then I found this and it worked the first time. So helpful
Tried it but it didn’t work for me. Back to the drawing board.
Hi Don, sorry to hear that! I can’t speak from personal experience here, but I have read that some have resorted to backing up and rebooting the phone as well. Be careful with this one though! I would love to hear if you find any additional solutions
Brilliant, thanks