L2TPv3 Traffic dropped as "Unknown IP Protocol Type"
03/26/2020 5 8463
If you're trying to set up a L2TP VPN between two devices (the SonicWall is not the L2TP server) and the traffic is being dropped as "Unknown IP Protocol Type" even if the access rules are configured to permit all the traffic to pass through the SonicWall.
The Service Object ANY does not include some IP types so when you create an access rule permitting all the traffic on ANY service, the Service Group ANY is not including the IP type you're using.
The L2TP is the protocol number 115 (IANA Protocol Numbers).
To configure the custom Service Object:
- Go to Firewall | Service Objects
- Add a new Service Object
Now create the following access rule, selecting as Service the Service Object you just created: