In an iOS application if you had to access corporate remote services, through VPN, what would be your pattern to ensure you have connectivity and inform the user if that's not the case:
- check that your network and VPN are working (by checking if some host like google.com and some private enterprise host are reachable) and if that's the case then call the remote service?
- or call directly the remote service, and if there is a network exception, then check if both a network host and an enterprise host are reachable? (to find-out what's going on and inform the user)
- or you would do it differently?
Usual approach:
1)User opens VPN client enables VPN connectivity
2)User uses the app.
Alternative approach:
If you are developing an enterprise application then you could possibly start and stop VPN connection right from the app using apple's private api.
Advantages of the approach:
So that all the network connections from the app are routed through VPN and user doesn't have to enable VPN connection every time he uses the app.
Reference:
You could find some hot discussions on this topic in the following threads.
来源：https://stackoverflow.com/questions/18671895/ios-enterprise-vpn-connectivity