netflector - the only mDNS / SSDP / DIAL / WSD / WoL reflector you will ever need

This is a tool that makes all kinds of multicast-based discovery (and casting) work across networks (or VLANs).

Full disclosure: I am using Claude Code. There are a lot of AI-sensitive people out there, so I want to be fully transparent this time. This post was not touched by AI, 100% human written :) Having said that, I am an experienced C++ developer (in HFT) and am writing low-level code (including networking) on a daily basis. This is not a vibe-coded project. I have designed this system and I have either written to reviewed all code.

With that out of the way, the main motivation behind this project for me was twofold: learn Rust and solve a real problem I have at home. My phone and my TV are in different VLANs, so vanilla multicast discovery does not work. While there are plenty of mDNS reflectors out there, my LG TV uses SSDP and DIAL. In order to cast YouTube from my phone to my TV following needs to happen:

• Phone sends M-SEARCH SSDP multicast request which needs to be reflected into TVs VLAN (other reflectors can do that).
• TV responds with the unicast 200 OK, which needs to be forwarded back to the phone. (can be allowed in firewall, less secure than using this tool).
• Phone initiates a device discovery TCP connection to TV (can be allowed in firewall, less secure than using this tool).
• TV replies with the details of its REST endpoint (works fine because established connections are usually allowed anyway).
• Phone initiates another TCP connection to TV's REST endpoint. The connection must be from the TV's subnet (could be allowed and NAT'ed in firewall).

So, to do this I would need to poke holes in the firewall and configure NAT. Additionally to that, I would still need to run some sort of reflector for SSDP multicast. How do I know? This is what I was doing for a couple of years :)

Not anymore. My tool does all that automagically:

• It reflects multicast discovery packets (mDNS / SSDP / WSD).
• It proxies unicast UDP responses (SSDP / WSD).
• It does NAT for TCP connections (DIAL).
• It supports MAC filtering (so only specific devices are discoverable).
• It tolerates network interface re-creation. As long as new interface has the same name - reflection will continue.
• And as a bonus, it also reflects Wake-on-Lan packets.

It does that with a very low footprint: static Linux binaries are <1MB. Right now it runs on my MikroTik router (as a container) and uses less than 3MB of RAM.

Currently I build static binaries for Linux (amd64/arm64/armv7/armv5) and FreeBSD (amd64/arm64), dynamic binaries for macOS (arm64) and a multi-arch Docker image. I will add more platforms on request.

I really hope that this project will be useful not only for me :)

GitHub: https://github.com/netflector/netflector

Feedback is welcome.