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

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:

1. 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

1. 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.

1. 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.