L2TPv3 Interfaces

L2TPv3 is a pseudowire protocol, you can read more about here Wikipedia L2TPv3 or RFC3921

L2TPv3 can transport any traffic including ethernet frames. L2TPv2 is limited to PPP.

L2TPv3 over IP

# show interfaces l2tpv3
l2tpv3 l2tpeth10 {
    address 192.168.37.1/27
    encapsulation ip
    local-ip 192.0.2.1
    peer-session-id 100
    peer-tunnel-id 200
    remote-ip 203.0.113.24
    session-id 100
    tunnel-id 200
}

Inverse configuration has to be applied to the remote side.

L2TPv3 over UDP

UDP mode works better with NAT:

Set local-ip to your local IP (LAN).
Add a forwarding rule matching UDP port on your internet router.

# show interfaces l2tpv3
l2tpv3 l2tpeth10 {
    address 192.168.37.1/27
    destination-port 9001
    encapsulation udp
    local-ip 192.0.2.1
    peer-session-id 100
    peer-tunnel-id 200
    remote-ip 203.0.113.24
    session-id 100
    source-port 9000
    tunnel-id 200
}

To create more than one tunnel, use distinct UDP ports.

L2TPv3 over IPSec, L2 VPN (bridge)

This is the LAN extension use case. The eth0 port of the distant VPN peers will be directly connected like if there was a switch between them.

IPSec:

set vpn ipsec ipsec-interfaces <VPN-interface>
set vpn ipsec esp-group test-ESP-1 compression 'disable'
set vpn ipsec esp-group test-ESP-1 lifetime '3600'
set vpn ipsec esp-group test-ESP-1 mode 'transport'
set vpn ipsec esp-group test-ESP-1 pfs 'enable'
set vpn ipsec esp-group test-ESP-1 proposal 1 encryption 'aes128'
set vpn ipsec esp-group test-ESP-1 proposal 1 hash 'sha1'
set vpn ipsec ike-group test-IKE-1 ikev2-reauth 'no'
set vpn ipsec ike-group test-IKE-1 key-exchange 'ikev1'
set vpn ipsec ike-group test-IKE-1 lifetime '3600'
set vpn ipsec ike-group test-IKE-1 proposal 1 dh-group '5'
set vpn ipsec ike-group test-IKE-1 proposal 1 encryption 'aes128'
set vpn ipsec ike-group test-IKE-1 proposal 1 hash 'sha1'
set vpn ipsec site-to-site peer <peer-ip> authentication mode 'pre-shared-secret'
set vpn ipsec site-to-site peer <peer-ip> authentication pre-shared-secret <pre-shared-key>
set vpn ipsec site-to-site peer <peer-ip> connection-type 'initiate'
set vpn ipsec site-to-site peer <peer-ip> ike-group 'test-IKE-1'
set vpn ipsec site-to-site peer <peer-ip> ikev2-reauth 'inherit'
set vpn ipsec site-to-site peer <peer-ip> local-address <local-ip>
set vpn ipsec site-to-site peer <peer-ip> tunnel 1 allow-nat-networks 'disable'
set vpn ipsec site-to-site peer <peer-ip> tunnel 1 allow-public-networks 'disable'
set vpn ipsec site-to-site peer <peer-ip> tunnel 1 esp-group 'test-ESP-1'
set vpn ipsec site-to-site peer <peer-ip> tunnel 1 protocol 'l2tp'

Bridge:

set interfaces bridge br0 description 'L2 VPN Bridge'
# remote side in this example:
# set interfaces bridge br0 address '172.16.30.18/30'
set interfaces bridge br0 address '172.16.30.17/30'
set interfaces ethernet eth0 bridge-group bridge 'br0'
set interfaces ethernet eth0 description 'L2 VPN Physical port'

L2TPv3:

set interfaces l2tpv3 l2tpeth0 bridge-group bridge 'br0'
set interfaces l2tpv3 l2tpeth0 description 'L2 VPN Tunnel'
set interfaces l2tpv3 l2tpeth0 destination-port '5000'
set interfaces l2tpv3 l2tpeth0 encapsulation 'ip'
set interfaces l2tpv3 l2tpeth0 local-ip <local-ip>
set interfaces l2tpv3 l2tpeth0 mtu '1500'
set interfaces l2tpv3 l2tpeth0 peer-session-id '110'
set interfaces l2tpv3 l2tpeth0 peer-tunnel-id '10'
set interfaces l2tpv3 l2tpeth0 remote-ip <peer-ip>
set interfaces l2tpv3 l2tpeth0 session-id '110'
set interfaces l2tpv3 l2tpeth0 source-port '5000'
set interfaces l2tpv3 l2tpeth0 tunnel-id '10'