Running Netflix on (common on the iPad 1) is extremely difficult today because Netflix has discontinued support for such old versions, and their servers often block outdated app versions from connecting. Current Status of Netflix on iOS 5.1.1

You have three better options than chasing a mythical IPA.

, and find Netflix. When you try to download it, iOS should offer to download the "last compatible version." Manual IPA Installation : You can find the Netflix v4.3.1 IPA file on archive sites like the Internet Archive . To install this, your device typically needs to be jailbroken to use tools like Sideloadly

If the App Store method fails, users often turn to digital archives to find the original .ipa file. Platforms like Internet Archive host collections of legacy software specifically for vintage iOS enthusiasts.

The most reliable way to get a compatible version without external files is to use your Apple ID purchase history