L2 LAN bridging over internet using L2TPv2+EoIP

The information on this page is updated in accordance with 00.07.03 firmware version.

Introduction

In this configuration example we will use L2TP with Ethernet over IP (EoIP) to bridge LAN interfaces between MikroTik and Teltonika devices. EoIP is a MikroTik RouterOS protocol based on GRE RFC 1701 that creates an Ethernet tunnel between two routers on top of an IP connection. The EoIP tunnel may run over the IPIP tunnel, PPTP tunnel, or any other connection capable of transporting IP.

Topology

Placeholder

Prerequisites

• MikroTik device(with L2TP and EoIP support) with Public IP (in this example we use hAP lite TC)
• Teltonika router or Gateway with Public IP (in this example we use RUTX11)
• Firmware with EoIP for Teltonika device
• A computer for testing and configuring the setup

Configuration of the Teltonika Device

From the Teltonika router, we will configure L2TP Client, EoIP, and firewall rules in order to achieve a working setup.

L2TP configuration

We will start by configuring the L2TP client. Open your device's WebUI and navigate to Services → VPN → L2TP, add a new L2TP client, once the configuration window opens, configure the client accordingly:

1. Enable the configuration
2. Server - input the MikroTik Public IP here
3. Username - username configurated on MikroTik server
4. Password - password configurated on MikroTik server 5.
5. Save the configuration

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Firewall configuration

In order for our configuration to work, we will need to update the Firewall. Navigate to the Network → Firewall → General Settings in the Zones section and change the L2TP zone settings to INPUT: Accept; OUTPUT: Accept; FORWARD: Accept; and disable the Masquerading. Upon changing these settings the configuration window should look like this:

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For the next part we will need access to the SSH/CLI of the device, we can reach device's CLI via System → CLI login with root username and password of your device.

Now we will add a new Firewall rule GRE Accept, for that you will need to execute these commands each one at a time(keep in mind that each command has to be executed in the order that has been provided below):

uci add firewall rule

uci set firewall.@rule[-1].name=GRE

uci set firewall.@rule[-1].target=ACCEPT

uci set firewall.@rule[-1].priority=14

uci set firewall.@rule[-1].src=l2tp

uci set firewall.@rule[-1].enabled=1

uci set firewall.@rule[-1].proto=47

uci set firewall.@rule[-1].utc_time=0

uci commit firewall && service firewall restart

Each command executed on the device should look like this:

You can confirm if the new rule was added with the command cat/etc/config/firewall the output should look like this:

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EoIP configuration

On the same CLI page we will execute additional UCI commands to configure, execute these commands each one at a time(keep in mind that each command has to be executed in the order that has been provided below):

uci add eoip eoip

uci set eoip.@eoip[-1].enabled=1

uci set eoip.@eoip[-1].name=0

uci set eoip.@eoip[-1].idtun=123

uci set eoip.@eoip[-1].dst=10.0.0.1

uci set eoip.@eoip[-1].dynamic=1

uci commit eoip

After that execute the command to start the EoIP service and check the status of it to confirm it is running with these commands:

/etc/init.d/eoip start

/etc/init.d/eoip status

The results of all of those commands should look similar to:

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Bridging the EoIP to LAN

Last step for Teltonika device is to bridge LAN interface with EoIP interface and changing the LAN interface to the DHCP Client, so the LAN would receive the IP from MikroTik device.