How to Configure LAN-to-LAN PPTP/L2TP VPN between UTT Routers

Introduction
This document describes how to configure LAN-to-LAN PPTP or L2TP VPN between two UTT AC750W. Configure VPN at two different places, one works as VPN Server, another works as VPN Client, users can visit each Intranet directly after establishing successfully.
 
Prerequisites
1. a UTT Business Router (hereinafter shorted as “the Router"), such as UTT router N518W, AC750W, AC750GW, AC1220GW, ER518, ER840G and ER4240G. Firmware Version: 3.0.0 or above
2. a PC/laptop connected to the Router wirelessly or through an Ethernet cable
 
Configuration
Network Diagram
1. VPN Server AC750W-1 Configuration
Create a VPN Server. Go to VPN > PPTP/L2TP, click Add. The same configuration on both PPTP and L2TP.
 
Tunnel Name: Specify a unique name for the VPN tunnel
Tunnel Type:
LAN-to-LAN: It allows two LAN sites to securely connect over the Internet. In this case, either a UTT VPN gateway or compatible VPN appliance can act as a VPN client
Mobile User: It allows remote individual users to securely connect over the Internet. In this case, a laptop or desktop computer will act as a VPN client
User Name/Password: Specify the user name and password for the VPN client
Remote Subnet IP Address/ Remote Subnet Mask: Specify the IP address and subnet mask of the remote network
 
2. VPN Client AC750W-2 Configuration
Create a VPN Client. Go to VPN > PPTP/L2TP, click Add. The same configuration on both PPTP and L2TP.
 
NAT Mode: It allows you to enable or disable NAT on the PPTP client. In this case, it can only allow unidirectional access from the LAN of PPTP client side to the LAN of server side
Tunnel Name: Specify a unique name for the VPN tunnel
Server IP/Domain Name: The public IP address or domain name of the remote VPN server
User Name/Password: Specify the user name and password for the VPN client
PPP Authentication: The PPP authentication mode must match on both ends of the tunnel
Remote Subnet IP Address/ Remote Subnet Mask: Specify the IP address and subnet mask of the remote network
 
3. Enable PPTP/L2TP at Global Settings on both server and client side, enter Primary DNS Server and click Save.
 
 
Troubleshoot
1. On VPN Server and VPN Client, can’t use the same LAN IP Address.
2. For the configuration of VPN Server and VPN Client, they must use the same Username and Password.
 
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