Accessing VSOL from LAN: A Raspberry Pi Bridge Setup

If you’ve ever wanted to access your VSOL ONU’s web interface (usually at 192.168.1.1) from your LAN (say 192.168.0.0/24), you might have hit a wall—especially if your router doesn’t allow assigning multiple WAN IPs. In this guide, I’ll walk you through how to bridge that gap using a Raspberry Pi or any other device with at least two network interfaces.

We’ll use the following setup

Prepare the Raspberry Pi

• Connect the Pi’s eth0 to your Router’s LAN port.
• Connect eth1 (USB-to-Ethernet adapter or secondary port) to ONU’s bridge port.

Your Pi now has two interfaces: one in your LAN and one going to the ONU.

Assign IP to Pi’s ONU-facing interface

The ONU doesn’t provide DHCP on its bridge port, so assign a static IP manually say 192.168.1.5/24 by running

sudo ip addr add 192.168.1.5/24 dev eth1

You can make this persistent using netplan or your preferred tool such that it doesn’t get lost after a reboot. Your Pi should be able to ping the ONU:

ping 192.168.1.1

Add a static route on your router

In your router’s web interface, go to Static Routing and add this route:

Now your router knows how to forward traffic for 192.168.1.0/24 through the Pi.

You will have to statically bind this address to your Pi so that it doesn’t change

Enable IP forwarding on the Pi

We need to allow Pi to forward IPv4 packets

sudo sysctl -w net.ipv4.ip_forward=1

For this to persist across reboot, edit /etc/sysctl.conf and add (or uncomment)

net.ipv4.ip_forward=1

Now, we need to setup IP forwarding rules using iptables command to allow forwarding across eth0 and eth1

# LAN to ONU
sudo iptables -A FORWARD -i eth0 -o eth1 -j ACCEPT

# ONU to LAN
sudo iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT

Since ONU doesn’t know how to return packets to your LAN, we will enable NAT

sudo iptables -t nat -A POSTROUTING -o eth1 -s 192.168.0.0/24 -d 192.168.1.0/24 -j MASQUERADE

iptables changes are lost after reboot. To persist them

sudo apt install iptables-persistent
sudo netfilter-persistent save

✅ All Done!

Now from any device in your LAN (192.168.0.x), just open a browser and head to http://192.168.1.1 to access the ONU’s management network.