iPhone 12 Pro Max - VPN Issue - Windows L2TP Server

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Epic007 Author

Level 1

10 points

iPhone 12 Pro Max - VPN Issue - Windows L2TP Server

I can't figure out the what the difference is between the iPhone 11 and iPhone 12 Pro Max VPN service.

Both phones running iOS v14.4.2

The iPhone 11 connects to my L2TP Server 2016 without problem.

The iPhone 12 Max will not connect to the same server with the same settings. Tried 5G and LTE.

I can see the packets on UDP port 4500 hitting the server from both phones. The 11 gets replies but the 12 Max does not. Suggests the 12 Max's initial packets are different, but what changed?

What's strange is if I connect to Nord VPN on the iPhone 12 Max, then try connecting to my L2TP Server through NordVPN, it works so I know the VPN settings are correct.

Why won't the 12 Max connect directly?

iPhone 12 Pro Max

Posted on Apr 15, 2021 3:10 PM

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Answer 1

Epic007 Author

Level 1

10 points

Apr 19, 2021 10:14 AM in response to Epic007

Still don't know what the difference is. It fails to complete the quick mode connection. Probably something to do with supported cipher proposal, though I don't know why it would be different between phones with the same software.

I just tore down the microsoft VPN server and switched to running the VPN server on my router. The router supports higher security levels anyway.

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