DHCP RELAY over L2TPv3

Introduction

A DHCP relay agent allows the DHCP clients to obtain IP addresses from a DHCP server that is not configured on the same LAN.

This article provides a configuration example with details on how to set-up a DHCP relay over a L2TPv3 VPN.

Prerequisites

You will need:

• Two RUT or RUTX devices (one as Server and other as Client)
• A PC acting as a Host for testing
• Both routers must have a Public Static or Public Dynamic IP addresses

Configuration Scheme

I will paste a Topology Image here

DHCP Server Settings

DHCP Pool

Enter the router's WebUI, go to Network > Interfaces > Ethernet LAN and click the 'Edit' button on the right side of the interface to set the LAN network address.

LAN network for DHCP server

Under DHCP SERVER set parameters for the DHCP pool.

DHCP pool parameters

Set up Mobile WAN as Main WAN

Enter to the router’s WebUI, go to Network > Interfaces press mouse click on the Mobile Wan interface, then drag it to the 1^st position and then press Save & Apply.

Mobile WAN as Main WAN

Create L2TPv3 instance

Go to router’s WebUI, under Service > VPN > L2TP > L2TPv3 and create new L2TPV3 instance.

LOCAL SETTING

Local address: 84.15.155.201

Tunnel ID: 100

Session ID: 100

Cookie: 12ABCDEF

PEER SETTING

Peer address: 84.15.249.182

Peer Tunnel ID: 10

Peer Session ID: 10

Peer Cookie: 12ABCDEF

INSTANCE SETTING

Bridge to: LAN

MTU: 1500

Encapsulation: IP

Layer 2 specific header type: Linux Default

L2TPv3 Server settings

L2TPv3 Server Settings