Detect VPN / Personal Hotspot

Question

Created Jun ’20

Replies 3

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Is there any reliable way to check for an active VPN connection or a connection over Personal Hotspot?

I am currently building an app that uses MultipeerConnectivity for peer-to-peer communication and from what I have learned so far MPC does not work with VPN / Personal Hotspot turned on.

To provide a first-class user experience (and tackle VPN problems in App Review) I want to check for a VPN / Personal Hotspot connection and display the user an alert encouraging him to disable the corresponding connection.
Just like AirDrop which should work quite similar to MPC.

I found this code snippet on Stackoverflow but since I do not really now anything about network interfaces in iOS I came here to seek help. :)

Code Block func isVPNConnected() -> Bool {
		let cfDict = CFNetworkCopySystemProxySettings()
		let nsDict = cfDict!.takeRetainedValue() as NSDictionary
		let keys = nsDict["__SCOPED__"] as! NSDictionary
		for key: String in keys.allKeys as! [String] {
				if (key == "tap"  key == "tun"  key == "ppp"  key == "ipsec"  key == "ipsec0") {
						return true
				}
		}
		return false
}

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Answer 1

maxxfrazer OP

Jun ’20

This is essentially the same as I use in my app. Although the keys could be slightly different, for example "tun0", "tun1" etc. So instead of exact matches my if statement looks like this:

Code Block if key.contains("tap") OR key.contains("tun") OR key.contains("ppp") OR key.contains("ipsec") {
  return true
}

(replace OR with ||, seems that the code formatting on the forums likes to replace them with underscores?)

1

Answer 2

Maci OP

Jun ’20

Thanks for your answer @maxxfrazer!

Did your app pass app review with that code?

And is there any chance that you know what network interfaces are being used for VPN / personal hotspot in iOS?

1

Answer 3

maxxfrazer OP

Jul ’20

@Maci Yes it finally got through, I was basically displaying a small toast message, warning that using a VPN may interfere with MultipeerConnectivity interfaces when I noticed it was switched on, and then the reviewer approved. No confirmation that this was indeed the fix, but I can assume it was.

I left warning messages rather than just leaving a blanket stop because some site-access VPNs are okay, it's only specific site-to-site VPNs that divert all network communications, and I do not know how to tell the differences between them.

1