I built an overlay network with a NAT gateway and offline LAN device access (cross-platform, experimental project)

edgeslink sdwan — Thu, 11 Dec 2025 08:00:41 +0000

Over the past months I’ve been experimenting with building a small overlay networking system to explore some limitations I often hit with existing tools like Tailscale or ZeroTier.

This is not a commercial product.
It’s an engineering exploration around:

NAT behavior inside an overlay
exporting LAN subnets
reaching offline / isolated devices
testing different node roles
cross-platform networking on macOS/Windows/Linux

I’m sharing it here to document the project and hopefully collect some technical feedback from the community.

🔧 Why I built this

Existing mesh/overlay systems are excellent—but I had three gaps I wanted to explore deeper:

Embedding a NAT Gateway inside the overlay

Most overlay networks tunnel traffic between nodes without providing a full internal NAT gateway.
I wanted to experiment with:

exporting local LAN subnets
routing remote peers into isolated networks
using the overlay as a security boundary
having a gateway node that acts as egress for others

Accessing offline LAN devices (USB-NIC scenario) In many industrial / IoT / camera / printer deployments:

Devices live on isolated LANs with no Internet
They expose only Ethernet
They cannot run an agent

By plugging a USB-NIC into a laptop/mini-PC running the overlay client, I can:

bridge the isolated LAN
expose selected devices to the overlay
manage them remotely without touching the LAN configuration

This has been surprisingly useful for cameras, printers, PLCs, and small embedded systems.

Multiple internal node roles

I introduced three simple node roles:

Edge – the standard client
Master (hub-like) – provides a stable anchor for peers
Direct-Relay – helps forward traffic between nodes when direct routing is impossible These roles are not SD-WAN standards, just internal behaviors I wanted to prototype.

🌐 Cross-platform support

The client currently works on:

macOS (Intel + Apple Silicon)
Windows
Linux

I wanted to ensure consistent routing and NAT behavior across systems, especially for:

exporting subnets
managing multiple interfaces
ensuring stable point-to-point links

🛠 Architecture overview

High-level components:

control plane for peer coordination
data plane based on encrypted P2P tunnels
NAT gateway module
USB-NIC detection + LAN export
fallback routing via relay nodes
peer metadata/state tracking If the HN/Dev community is interested, I can publish a full architecture breakdown.

🔗 Project link

https://www.edgeslink.com

📬 Contact (optional)

If anyone wants to discuss deeper technical details:

Email: edgeslinksdwan@gmail.com
Telegram: https://t.me/edgeslink

🙏 Thanks for reading

Happy to answer questions or elaborate on any part of the project.

DEV Community: edgeslink sdwan

I built an overlay network with a NAT gateway and offline LAN device access (cross-platform, experimental project)