L2TP VPN configuration iOS 14

App & System Services Core OS
Hatem91salameh OP
Created Sep ’20
Replies 42
Boosts 0
Views 22k
Participants 31
with the new iOS 14 update now the VPN I configure is not working it keeps showing:
"The l2TP-VPN server is did not respond. try reconnecting. if the problem continues, verify your settings and contact your admin."
but if I try on my other iphone which runs ios 13.7 it connects fine with the same exact settings.
How can I fix that
Replies  42
Boosts  0
Views  22k
Participants  31
Cutezjz OP
Sep ’20
faced the same issue, looks like a widely iOS14 bug for L2TP VPN connection.
barchettaplayer OP
Sep ’20
same problems with our company VPN...
iPad iOS 13.6 works fine
iPad iOS 14 "The l2TP-VPN server is did not respond. try reconnecting. if the problem continues, verify your settings and contact your admin."

same on iPhone and iOS14
Systems Engineer OP
Apple
Sep ’20
Can you please file a Bug Report here with a complete description of what you are seeing on iOS 14. Also, as you will most likely be asked, please include a sysdiagnose that is taken after you have reproduced he issue. Please include the following debug profiles on your device before you take the sysdiagnose:

  • CFNetwork

  • Network Diagnostics

  • VPN (Network Extension)

Please note the time and date you reproduced the issue and mention this on your bug report.
Please follow up with the Feedback ID when you have done so.


Matt Eaton
DTS Engineering, CoreOS
meaton3@apple.com
Frank-ME81 OP
Sep ’20
I have the same issue on iPad 2018 with IPadOS 14
rustter OP
Sep ’20
Same issue on iPhone SE with iOS 14
0dmin OP
Sep ’20
Same problems with l2tp. iPhone 7 iOS 14.
migaspar OP
Sep ’20
same here. VPN via L2TP is not working. iOS 14.0 (18A373) on iPhone SE (2020).
Hatem91salameh OP
Sep ’20
@meaton I already reported a bug on feedback assistant for this issue



Systems Engineer OP
Apple
Sep ’20
@Hatem91salameh Thank you. What is you Feedback ID and did you also include a sysdiagnose with the instructed information that I provided?


Matt Eaton
DTS Engineering, CoreOS
meaton3@apple.com
pzhang1357 OP
Sep ’20
Same issue here. L2TP does not connect on ios14 while ios13 and os x 10.13.2 works fine.
ParhamB OP
Sep ’20
I have same issue with iPhone 11 Pro and iOS 14, but this connection has work properly on iOS 13.7.
rickysuper OP
Sep ’20
Same issues with my iPad mini upgraded to PadOS 14. Any fix or settings can provide ?

Thanks
rustter OP
Sep ’20
@meaton I have submitted feedback with your debug profiles. Feedback ID is FB8713513.
Luyegang OP
Sep ’20
sha2-truncbug=yes

delete this in your ipsec config, and it worked.

I use libreswan+xl2tpd
rickysuper OP
Sep ’20
if remark sha2-truncbug=yes or change to sha2-truncbug=no, other devices may not be connect.
stuartr75 OP
Sep ’20
Same issue here when trying to a Draytek 2820 that worked fine on 13.7. It does work fine on other L2TP VPN’s I have setup with other routers, mainly Draytek 2860’s. iPhone 11 & iPhone 7
dominikconrads OP
Sep ’20
Apple responded to my report with the following:

This will need to be resolved by the server administrator.

We have upgraded the proposed ciphers in L2TP IPsec VPN to also propose SHA-256 for the Child SA in IPsec. The issue seems to be that the server is accepting SHA-256 cipher for the child but maybe dropping the ESP encrypted packets with SHA-256 HMAC. This maybe because the server is assuming a SHA-256 HMAC with 96 bits instead of the standard 128 bits. Switching the SHA-256 HMAC output from 96 to 128 bits should fix this issue.

Thank you for your feedback.

I have now disabled the SHA-256 compatible mode (96 bit) on my VPN server and now it works.
Frank-ME81 OP
Sep ’20
@dominikconrads, it is nice that it works for you.
But all other still have the issue, so i would say apple should test that, and bring a solution.
In my case, we have sophos utm 9 in our company, and on all updated iphones and ipads
L2TP doesn't work anymore.

BR
Frank
stuartr75 OP
Sep ’20
Draytek have no plans to update this for the older routers 2820 model. I can connect to the newer models of Draytek's 2860 e.t.c.

I'm sure there are plenty of older routers that would not support this. Could this get changed back at all Apple and everyone should be happy:) ? Especially with a lot of people trying to work from home at the mo.


"This will need to be resolved by the server administrator.
We have upgraded the proposed ciphers in L2TP IPsec VPN to also propose SHA-256 for the Child SA in IPsec. The issue seems to be that the server is accepting SHA-256 cipher for the child but maybe dropping the ESP encrypted packets with SHA-256 HMAC. This maybe because the server is assuming a SHA-256 HMAC with 96 bits instead of the standard 128 bits. Switching the SHA-256 HMAC output from 96 to 128 bits should fix this issue."
oowv OP
Sep ’20
Same issue on iPhone XR and iPad Pro with iOS 14.
I am not able to connect to our L2TP-VPN.
Other Devices with iOS 13 work fine.
rickysuper OP
Sep ’20
Sadly that 14.0.1 still not fixed. I need to change my devices to android system. My router is Draytek 2906 but official support do not know if the latest firmware can support IOS14 or not.
JeromeGREZ OP
Sep ’20
Same issue with iPhone SE 2. Nothing best with upgrade IOS 14.0.1
Goma777 OP
Sep ’20
Same issue here! No more connection to our VPN for those who updated to iOS 14 :-( very annoying even more with the current situation where we have to remote work!
Qixin OP
Sep ’20
I think that when the VPN is connected, the iPhone’s network is interrupted and then reconnected when the VPN tunnel is successfully established, and iOS14 may not interrupt the network connection.
After testing, I found that if after the first VPN connection, if the network is found to be interrupted, then turn on the airplane mode, and then immediately turn off the airplane mode, which is equivalent to the user manually disconnecting and reconnecting, then the VPN network is immediately available.
Lisovskiy OP
Sep ’20
The same issue with iPhone X 😔
L2TP VPN configuration iOS 14
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