IPad – prevent an iPad app ever being updated

You should be able to filter your firewall logs down to requests originating from your computer/your phone's local IP address, and look it it's outgoing requests.

I'm pretty sure all that app download traffic takes place over bog standard HTTPS, 443/tcp.

Ensure all apps have stopped running, open App Store, move over to the Updates category, wait for all traffic (app image requests and the like) to die down, then tap update. The next series of requests should fail, and you should have the reason relevant to your own configuration.

First, you should authorize your computer with your iPad if you haven't already.

1. From the Store menu, choose Authorize Computer.
2. In the dialog that appears, the Apple ID button is selected by default. If you have an AOL account, select AOL.
3. Enter your Apple ID or AOL screen name and password, then click the Authorize button.

Then, transfer your purchases:

From the File menu, choose "Transfer Purchases from "Lipis' iPad" "

Wait for iTunes to complete the transfer.

Check in your library for your apps and the like.

Then you can sync without worry.