Cannot connect to L2TP VPN from iOS devices

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Level 1

47 points

Cannot connect to L2TP VPN from iOS devices

This weekend I decided to perform a hard drive upgrade on my little 2009 Mac mini that I run as a homespun server as a hobby. In the process, I thought it would be worthwhile to flatten the whole thing and start again from fresh.

However, in doing so, I no longer seem to be able to connect to it's VPN from an iOS device. Both my iPhone 6 (iOS 8.1.3) and iPad 3rd Gen (iOS 8.1.3) cannot connect to the VPN server over an L2TP connection – either on my local network or over 3G, even if the local IP is provided instead of a host name.

Interestingly though, my MacBook Pro has no issues connecting over L2TP when tethered to my iPhone's 4G. It can dial back home and authenticate successfully.

The settings are exactly the same on both as both are governed under a single profile containing the VPN settings and login details.

It used to work before the hard drive upgrade, but can't remember the last time I used VPN on my iPhone. Just wondering if this is a bug in iOS 8.1.x?

iOS reports "The L2TP-VPN server did not respond". Additionally, there is absolutely nothing in the Server's console for VPN or 'racoon'. In the past when I've had issues, the connect is made but doesn't authenticate or some such. This just doesn't get to the server in any way shape or form.

Any ideas?

Posted on Feb 28, 2015 7:29 AM

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Answer 1

Mar 18, 2015 7:43 AM in response to jamie.shaw

I believe the problem is in iOS, as I am experiencing the same issue.

I have a Yosemite Server running L2TP VPN server and my Mac connects flawless, while neither the iPhone nor the iPad (both 8.2) are able to connect.

The error is the same "The L2TP-VPN server did not respond" and by looking at the server's log it seems iOS didn't even try to connect.

I have tried changing the server address in iOS with the corresponding IP, but the results it's the same.

Maybe a network setting reset?

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Answer 2

jamie.shaw Author

Level 1

47 points

Mar 18, 2015 8:39 AM in response to AlessandroDN

I managed to find the cause of my issue, but forgot to post on here – I forgot I had post this thread at all.

For me, it was an issue with the shared secret, I was using a randomly generated sting of ASCII characters including symbols and for some reason, one of the symbols (I've not exhausted time to discover which) was causing an issue with iOS connections. I swapped the shared secret out for a purely alphanumeric random string and it worked straight away. Dropped a different symbol-inclusive string back in and it stopped again.

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