SnapGear 2.0.1 - Manual (Page 161)

Virtual Private Networking
157
L2TP
The Layer Two Tunneling Protocol was developed by Microsoft and Cisco as a multi-
purpose network transport protocol.
Many DSL ISPs use L2TP over ATM to create tunnels across the Internet backbone.
The CyberGuard SG L2TP implementation can only run L2TP over Ethernet since it
doesn't have an ATM adapter. L2TP packets are encapsulated in UDP packets on port
1701 and sent over Ethernet to the L2TP server.
L2TP VPN client
The CyberGuard SG L2TP VPN client is configured and operates in a similar way to the
PPTP VPN Client.
Figure 9-30