DHCP RELAY over L2TPv3: Difference between revisions

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* A PC acting as a Host for testing
* A PC acting as a Host for testing
* Both routers must have a Public Static or Public Dynamic IP addresses
* Both routers must have a Public Static or Public Dynamic IP addresses
== Configuration Scheme ==
[[File:Topology LT2Pv3.png|border|class=tlt-border|750x750px]]
== DHCP Server Settings ==
=== DHCP Pool ===
Login to the router's WebUI and navigate to '''Network → Interfaces → Ethernet LAN.''' Click the '''<nowiki/>'Edit'''' button on the right side of the interface to set the LAN network address.
[[File:Server new 01 fixed.png|border|class=tlt-border|750x750px]]
Under '''DHCP SERVER''' set parameters for the DHCP pool.
[[File:Server new 02 1 fixed.png|border|class=tlt-border|750x750px]]
===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<sup>st</sup> position and then press '''Save & Apply'''.
[[File:Server new 03 fix.png|border|class=tlt-border|750x750px]]
===Create L2TPv3 instance===
Go to router’s WebUI, under '''Service → VPN → L2TP → L2TPv3''' and create new '''L2TPV3''' instance.
'''LOCAL SETTING'''
Local address: 84.15.XXX.XXX
Tunnel ID: 100
Session ID: 100
Cookie: 12ABCDEF
'''PEER SETTING'''
Peer address: 84.15.XXX.XXX
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
[[File:Server new 04 01 fix.png|border|class=tlt-border|750x750px]]
[[File:Server new 04 02.png|border|class=tlt-border|750x750px]]
'''Note:''' Specify on "Local address" your mobile WAN public IP. Local value for Tunnel ID, session ID and Cookie must match with the peer values being used at the other end.
==DHCP Client Settings (Relay) ==
===DHCP Relay===
Enter the router's WebUI, go to '''Network → Interface → LAN → DHCP Server''' and change the "'''Enable DHCP'''" field value from Enable to Relay and type in the DHCP Server the IP address of the server. Click '''Save & Apply'''.
[[File:Client 01 fix.png|border|class=tlt-border|750x750px]]
'''Note:''' The IPv4 address of the LAN interface is different from the server's LAN interface address, this is necessary to avoid conflicts.
===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<sup>st</sup> position and then press '''Save & Apply'''.
[[File:Client 02 fix.png|border|class=tlt-border|750x750px]]
===Modify Enable-DHCP-renew firewall rule===
Enter in the router’s WebUI, go to '''Network → Firewall → Traffic rules''' to additionally allow destination port 67.
[[File:Client 03.png|border|class=tlt-border|750x750px]]
===Create L2TPv3 instance===
Go to router’s WebUI, under '''Service → VPN → L2TP → L2TPv3''' and create new '''L2TPV3''' instance.
'''LOCAL SETTING'''
Local address: 84.15.XXX.XXX
Tunnel ID: 10
Session ID: 10
Cookie: 12ABCDEF
'''PEER SETTING'''
Peer address: 84.15.XXX.XXX
Peer Tunnel ID: 100
Peer Session ID: 100
Peer Cookie: 12ABCDEF
'''INSTANCE SETTING'''
Bridge to: LAN
MTU: 1500
Encapsulation: IP
Layer 2 specific header type: Linux Default
[[File:Client 04 fix.png|border|class=tlt-border|750x750px]]
[[File:Server new 04 02.png|border|class=tlt-border|750x750px]]
'''Note:''' Specify on "Local address" your mobile WAN public IP. Local value for Tunnel ID, session ID and Cookie must match with the peer values being used at the other end.
==Testing DHCP over L2TPv3==
To test the realy settings go to DHCP server to check that devices are able to recieve IP addresses in the range 192.168.10.150 - 192.168.10.170 either via LAN port or Wi-Fi. Access the CLI  and run '''cat /tmp/dhcp.leases''' to list all DHCP clients.
[[File:Test 01 fix.png|border|class=tlt-border|750x750px]]
Asking for the Address Resolution Protocol (ARP) table is also an other method to find hosts on the LAN network.
[[File:Test 02 fix.png|border|class=tlt-border|750x750px]]
[[Category:Use cases]]

Revision as of 01:59, 18 March 2022

Main Page > General Information > Configuration Examples > Use cases > 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