This article shows how to configure an IPSec site-to-site VPN (with USG series) using VTI (Virtual Tunnel Interface). The following instructs how to configure the VPN tunnel between each site. When the VPN tunnel is configured, each site can be accessed securely

Note: All network IP addresses and subnet masks are examples. Please replace them with your actual network IP addresses and subnet masks. This example was tested using the USG40 and the USG60 (Firmware version: ZLD 4.20).

1) Configure IPSec VPN Tunnel on Headquarter's USG60 (HQ-USG60)

1.1 Configure VPN Gateway

In the USG60's web configurator, go to CONFIGURATION > VPN > IPSec VPN >VPN Gateway and create a VPN rule that can be used with the remote USG.

CONFIGURATION > VPN > IPSec VPN >VPN Gateway

1.2 Configure VPN Connection

Configure the VPN connection as the following.

CONFIGURATION > VPN > IPSec VPN > VPN Connection

1.3 Configure the VTI Interface

Configure a VTI interface that corresponds with the VPN rule.

Configuration > Network > Interface > VTI

2) Configure IPSec VPN Tunnel on Branch Office's USG40 (BO-USG40)

2.1 Configure VPN Gateway

In the USG40's web configurator, go to CONFIGURATION > VPN > IPSec VPN >VPN Gateway and create a VPN rule that can be used with the remote USG.

CONFIGURATION > VPN > IPSec VPN >VPN Gateway

2.2 Configure VPN connection

Configure the VPN connection as the following.

CONFIGURATION > VPN > IPSec VPN > VPN Connection

2.3 Configure VTI Interface

Configure a VTI interface that corresponds with the VPN rule.

Configuration > Network > Interface > VTI

2.4 Connect the VPN tunnel

Go back to CONFIGURATION > VPN > IPSec VPN >VPN connection and click Connect.

CONFIGURATION > VPN > IPSec VPN >VPN Connection

2.5 Check the VTI Connection Status

Once the VPN connection is established, the VTI interfaces on both HQ-USG60 and BO-USG40 are activated. 

• HQ-USG60

• BO-USG40 

3) Configure the Policy Route on HQ-USG60

3.1 Configure LAN Object & Policy Route

Create an object for the BO_LAN1 subnet.

CONFIGURATION > Object > Address/Geo IP

Then configure the policy route.

CONFIGURATION > Network > Routing > Policy Route

4) Configure the Policy Route on BO-USG40

4.1 Configure LAN Object & Policy Route

Create an object for the HQ_LAN1 subnet.

CONFIGURATION > Object > Address/Geo IP

Configure the policy route.

CONFIGURATION > Network > Routing > Policy Route

5) Test the IPSec VPN Tunnel 

1.     Go to HQ-USG60's  MONITOR > VPN Monitor > IPSec screen and check the tunnel's Up Time and Inbound(Bytes)/Outbound(Bytes) traffic.

MONITOR > VPN Monitor > IPSec

2.     To test whether or not a tunnel is working, ping from a computer at one site to a computer at the other. Ensure that both computers have Internet access (via IPSec devices).

PC at HQ Office: Windows 7 > cmd > ping 192.168.20.34

PC at Branch Office: Windows 10 > cmd > ping 192.168.10.33