Open Radar

 
Summary:
iOS does not provide functionality to associate internal URLs which cannot be reached from the internet with an application. There should be the possibility to open an (enterprise) application when a link to an internal URL is opened.

Steps to Reproduce:
Example: A company has a domain foo.bar in its internal network. The domain is only reachable from within the company’s network.
The company also provides an enterprise signed iOS application FooBar which should be opened when the user tries to open a link which points to the foo.bar domain. The user’s device is not in the company’s network, thus the web server on foo.bar containing a apple-app-site-association file cannot be reached.

Expected Results:
When the user opens a link with the foo.bar domain the associated app is opened

Observed Results:
Since the domain foo.bar is not reachable via the internet the associated application cannot be opened.

Version:
iOS 10, iOS 11

Notes:
A solution to this problem could be the distribution of apple-app-site-association files for Universal Links using Configuration Profiles. This would allow a company to associate an internal domain with one of their internal apps. The Configuration Profiles could be distributed with existing mobile device management solutions. 

It is actually possible to associate an internal domain with an iOS app when the user has accessed domain at least once (e.g. when the user’s device has been in the company’s internal network). The connection between app and domain is cached by iOS for on unspecified duration. This approach is not suitable for large scale enterprise environments.

An internal domain could also be made available by using a VPN. This is no alternative to distributing the site association via mobile device management, it cannot be guaranteed that a VPN for iOS devices is available in a company’s IT infrastructure.