How to setup a Site-to-Site VPN connection between two ZyWALL/USG series appliances.

Introduction

This guide will explain how to configure a site-to-site VPN connection as shown in the picture below using the Express VPN Wizard:
For instructions on using the Advanced VPN Wizard please click here.

In the above scenario, the clients at the Branch office wants to be able to access the Headquarters entire LAN subnet and vice versa. The setup will be the same regardless what ZyWALL/USG model you are using. In this example we will be looking at a two USG60's.

Express VPN Wizard

Login to the USG WebUI and go to the Configuration() menu.  From here click the Quick Setup() option at the top of the menu list.

Once the wizard window opens select the VPN Setup option.

The VPN setup wizard supports the option to create Site-to-Site, Client-to-Site and/or L2TP VPN connection.  In this scenario we are connecting two USG60 gateways which would require a Site-to-Site connection.  To create this connection select VPN Settings and click Next.

By default the VPN wizard will run in Express mode.  Click Next to continue with the VPN configuration.

Provide the following details on the screen below for the VPN setup.

• IKE Version - IKEv1 or IKEv2 [IKEv2 is highly recommended]
• Rule Name - Provide a name for the VPN rule
• Select Site-to-Site for the application scenario
• Click Next to continue
  

On the next screen provide the following details:

• My Address - Select the WAN interface you wish to use for the VPN
• Secure Gateway - Provide the WAN IP/FQDN/DDNS for the remote appliance
• Pre-Shared Key - Create a key [this key must match on both sites]
• Local Policy - Type the IP and mask for the local network [the IP entry specifies what addresses the remote network will be able to communicate with]
• Remote Policy - Type the IP and mask for the remote network [the entry specifies what addresses the local network will be able to communicate with on the remote location]
• Click Next to continue
  

A summary of the setup will show on the following screen.  Copy the text in the "Configuration for Secure Gateway" box and paste it on a text editor (Notepad, Notepad++, TextEdit, etc.).  Save the text file with a ZYSH extension (example: Script_From_Branch_Office.zysh), this file will be uploaded on the remote appliance to configure the VPN.  Click Save to complete the VPN wizard.

Click Close to end the wizard configuration.

Remote Appliance Setup

Login to the USG WebUI and go to menu, Maintenance() → File Manager and click on the Shell Script tab.  Click the Browse button to search for the "Script_From_Branch_Office.zysh" file and Upload it.

Once the script is uploaded to the remote VPN appliance, Apply it.  This will create the matching VPN rule (on remote VPN router) based on the settings selected through the VPN wizard on the primary appliance.

Select Yes to continue with the script loading.

Establish connection

Both ZyWALL/USG devices are now configured. The only thing left, is to establish the VPN connection. This can be done manually by selecting your VPN connection and clicking the Connect button in Configuration() → VPN → IPSec VPN → VPN Connection. Alternatively you can edit the VPN Connection rule, click "Show Advanced Settings" and enable Nailed-Up. With Nailed-Up enabled the VPN tunnel will connect up automatically when the ZyWALL/USG boots up.

All devices at the Branch Office will now be able to access devices and computers on the Headquarters subnet and vice versa.