Overview
mdnsbridge listens for mDNS/Bonjour service announcements on one network interface and re-announces them on another, making services visible across VLANs, containers, and VM networks without a full multicast router. A single static binary, no daemon configuration.
How it works
Uses Go's raw multicast socket support to join the mDNS group (224.0.0.251:5353) on each configured interface. Incoming DNS-SD packets are parsed, filtered by service type if desired, and re-emitted on the target interface with TTL adjusted to prevent loops. Runs as a lightweight systemd service or inside a container with host networking.
Features
Cross-VLAN discovery
Bridge mDNS between a home VLAN and a server VLAN so printers, AirPlay speakers, and Chromecast devices stay discoverable.
Container-aware
Works with Docker bridge networks and macvlan setups where mDNS doesn't cross the virtual interface boundary.
Service type filtering
Optionally relay only specific service types (e.g. _airplay._tcp, _http._tcp) to reduce noise on the target segment.
Single static binary
Compiled Go — no runtime, no dependencies, drops into any Linux system or minimal container image.
Loop prevention
Tracks recently forwarded records and suppresses re-forwarding to avoid amplification loops in meshed networks.
Architecture
Posts
2026-04-26
Notes for April 20-26