Здравствуйте!

Роутер ER7206, управляемый Omada Controller. Мы создали Client-to-Site VPN L2TP(Server) для подключения сотрудников к внутренней сети. На Windows и на Mac клиенты подключаются без проблем, на Ubuntu 20.04 и 16.04 подключиться не получается, вот кусок дебага:

** Message: 12:08:15.619: Check port 1701
** Message: 12:08:15.619: Can't bind to port 1701
nm-l2tp[2955] <warn>  L2TP port 1701 is busy, using ephemeral.

m-l2tp[2955] <info>  starting ipsec
Stopping strongSwan IPsec failed: starter is not running
Starting strongSwan 5.8.2 IPsec [starter]...
Loading config setup
Loading conn '93bd12cf-4bff-4f4c-95c2-e8781856cc1b'
nm-l2tp[2955] <info>  Spawned ipsec up script with PID 3009.
initiating Main Mode IKE_SA 93bd12cf-4bff-4f4c-95c2-e8781856cc1b[1] to 92.242.xxx.xxx
generating ID_PROT request 0 [ SA V V V V V ]
sending packet: from 192.168.179.187[500] to 92.242.xxx.xxx[500] (532 bytes)
received packet: from 92.242.xxx.xxx[500] to 192.168.179.187[500] (132 bytes)
parsed ID_PROT response 0 [ SA V V V ]
received XAuth vendor ID
received DPD vendor ID
received NAT-T (RFC 3947) vendor ID
selected proposal: IKE:3DES_CBC/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024
generating ID_PROT request 0 [ KE No NAT-D NAT-D ]
sending packet: from 192.168.179.187[500] to 92.242.xxx.xxx[500] (244 bytes)
received packet: from 92.242.xxx.xxx[500] to 192.168.179.187[500] (244 bytes)
parsed ID_PROT response 0 [ KE No NAT-D NAT-D ]
local host is behind NAT, sending keep alives
generating ID_PROT request 0 [ ID HASH ]
sending packet: from 192.168.179.187[4500] to 92.242.xxx.xxx[4500] (68 bytes)
sending retransmit 1 of request message ID 0, seq 3
sending packet: from 192.168.179.187[4500] to 92.242.xxx.xxx[4500] (68 bytes)
nm-l2tp[2955] <warn>  Timeout trying to establish IPsec connection
nm-l2tp[2955] <info>  Terminating ipsec script with PID 3009.
Stopping strongSwan IPsec...
destroying IKE_SA in state CONNECTING without notification
establishing connection '93bd12cf-4bff-4f4c-95c2-e8781856cc1b' failed
** Message: 12:08:28.824: Could not establish IPsec connection.

Настройки при этом следующие:

Пробовали установить разные методы аутентификации, пробовали включать/выключать галки.

Для примера ещё покажу конфиг на клиенте на Windows, который работает:

Add-VpnConnection -Name "ESNvpn" -ServerAddress "92.242.xxx.xxx" -TunnelType L2TP -L2tpPsk "pre-shared_key_here" -AuthenticationMethod "MSChapv2" -Force

Подскажите, пожалуйста, какой конфиг для Ubuntu надо использовать?