L2Tp Vpn; Overview; What You Can Do In This Chapter; What You Need To Know - ZyXEL Communications ZyWall USG20-VPN User Manual

25.1 Overview

L2TP VPN uses the L2TP and IPSec client software included in remote users' Android, iOS, Windows
or Mac OS X operating systems for secure connections to the network behind the USG. The remote
users do not need their own IPSec gateways or third-party VPN client software.
Figure 276 L2TP VPN Overview

25.1.1 What You Can Do in this Chapter

• Use the L2TP VPN screen (see
settings.
• Use the VPN Setup Wizard screen in Quick Setup
USG's L2TP VPN settings.

25.1.2 What You Need to Know

The Layer 2 Tunneling Protocol (L2TP) works at layer 2 (the data link layer) to tunnel network traffic
between two peers over another network (like the Internet). In L2TP VPN, an IPSec VPN tunnel is
established first and then an L2TP tunnel is built inside it. See
information on IPSec VPN.
IPSec Configuration Required for L2TP VPN
You must configure an IPSec VPN connection prior to proper L2TP VPN usage (see
page 396 for details). The IPSec VPN connection must:
• Be enabled.
• Use transport mode.
• Use Pre-Shared Key authentication.
• Use a VPN gateway with the Secure Gateway set to 0.0.0.0 if you need to allow L2TP VPN
clients to connect from more than one IP address.
C
HAPTER
Section 25.2 on page
USG20(W)-VPN Series User's Guide
396

L2TP VPN

397) to configure the USG's L2TP VPN
(Chapter 4 on page 50) to configure the
Chapter 21 on page 333
2 5
for
Chapter 25 on