Port Zero

Frequently looked up

Q1Why doesn't Port Zero use real mDNS (Bonjour/Avahi .local names) instead of its own portzero.local domain?

Port Zero chose its own portzero.local domain to avoid collision risks with mDNS addresses on the LAN, improve security by keeping local dev services reachable only from the local machine, ensure reliability offline and on networks that filter multicast, and reduce protocol complexity. Real mDNS would expose unauthenticated dev services to anyone on the same network, expanding attack surface unnecessarily.

Q2Does Port Zero break Bonjour/AirPrint/Avahi?

No. Port Zero claims only the portzero.local subtree using a scoped resolver entry that sends queries for portzero.local to Port Zero's DNS server. Every other .local name—printer.local, AirDrop, etc.—still goes to mDNSResponder/Avahi as before. Port Zero never answers or announces on multicast.

Q3How does Port Zero handle local tunnels technically?

Port Zero's daemon creates a virtual network interface (TUN device) on your machine and assigns stable virtual IPs to processes by name. It builds a private DNS record for each stable domain, forwards the specified port to the actual ephemeral port, and proxies TCP connections. This works for any TCP protocol, not just HTTP, and requires elevated privileges for the local overlay.

Q4Can you set up a local tunnel inside a remote or browser coding session?

Yes, it works with one extra step. Install Port Zero, start the daemon as root (since the overlay needs elevated privileges), tag your process with PZ_TUNNEL as usual, and manually add a hosts entry if automatic OS-level DNS is not available in the sandbox.