Zyxel Nebula [NSG] - Configure L2TP VPNbehind NAT

This guide will help you if you need an L2TP VPN with an NSG, which is behind NAT (local WAN IP).

The issue is, that the predefined local policy object for the L2TP VPN uses the WAN IP.
This will cause an L2TP local policy mismatch!

Please access the NSG via SSH and enter the following commands:

Router> configure terminal
Router(config)# address-object L2TP_WAN 0.0.0.0
Router(config)# write

You won't run into the policy mismatch error with this change and your client will successfully connect to the NSG.