DUO Radius Unifi L2TP VPN issue

[Com7IT]

Hi,

I have a problem getting a Duo Mobile Push notification after authenticating VPN access from Windows 10 L2TP Vpn client.

The setup is:

• Radius server is running on a Unifi dream machine pro
• Duo authentication Proxy is running on a Ubuntu 20.04LTS on Windows 10 WLS2
• The vpn user is created in the admin portal With Duo Mobile already setup
• Latest version of DAP is installed on Ubuntu and configuration scripts show no errors and is up
• Windows 10 21H1 L2tp vpn client that is able to connect with username/password
• The firewalls are off and both Ubuntu and UDM pro (latest firmware!) can ping eachother

But the Duo Mobile never gets a push and there is never a 2FA happening.

I have followed all the guides and read all past threads online.

Running TCPdump on Ubuntu shows no Radius authentication requests being made at all

The config:

[radius_client1]
host=192.168.0.1 (UDM pro)
secret=hidden
port=1816
pass_through_all=true

[radius_server_auto3]
ikey=hidden
skey=hidden
api_host=hidden
radius_ip_2=172.26.0.0/20 (LAN that Ubuntu is on in WSL2)
radius_secret_2=hidden
failmode=safe
client=radius_client1
port=1816

I have tried back an fourth with different configs and this is the newest.

[DuoKristina]

If no incoming RADIUS requests are arriving at the Ubuntu system that is running the Duo Authentication Proxy then you should re-examine whatever is supposed to be sending RADIUS requests to it to make sure it’s actually configured to do so.

radius_ip_x should be whatever is configured to send the outbound RADIUS access request to the Duo proxy server on port 1816.