From be2477d32673f00bd608c7bd294edfd9c1d03d0c Mon Sep 17 00:00:00 2001 From: Franck Zoccolo Date: Wed, 5 Aug 2026 10:50:54 +0200 Subject: [PATCH] Document IPv6 support in README --- README.md | 3 +++ 1 file changed, 3 insertions(+) diff --git a/README.md b/README.md index abddcda..c8e1687 100644 --- a/README.md +++ b/README.md @@ -1,5 +1,7 @@ This is a **Discovery Proxy for Multicast DNS-Based Service Discovery**, written in pure Python. It makes use of [zeroconf](https://pypi.org/project/zeroconf/) to obtain mDNS advertisements on the local network and [Twisted](https://pypi.org/project/Twisted/) to re-publish them as a unicast DNS service. +Both IPv4 and IPv6 are supported on the mDNS side. For IPv6, only Unique Local Addresses (ULA, `fc00::/7`) are published in `AAAA` records: link-local addresses aren't usable by unicast DNS clients (DNS has no way to express the required zone index), and globally routable addresses are filtered out so that only internal ULA addresses are advertised. + This kind of proxy is specified by [RFC 8766](https://tools.ietf.org/html/rfc8766). I did not actually follow the standard in implementing it, which means that it doesn't abide by many of the finer details. Nevertheless, it works fine with clients like macOS 10.15 and iOS 13. Any violations of the standard are to be considered bugs and should be fixed over time. Other implementations of discovery proxies are [ohybridproxy](https://github.com/sbyx/ohybridproxy) and [included with mDNSResponder](https://opensource.apple.com/source/mDNSResponder/mDNSResponder-1096.60.2/ServiceRegistration/dnssd-proxy.c.auto.html). Since the former only runs on OpenWRT and mDNSResponder is not readily available on Linux, I decided to put together my own implementation in Python. Its dependencies are pure Python, so it should be possible to run it pretty much anywhere. @@ -22,6 +24,7 @@ ptr-record=db._dns-sd._udp.example.com,home.arpa To check whether it is working, you can try some of the following queries (assuming your computer is named _yourcomputer_ and advertises an SSH service): ```bash dig yourcomputer.home.arpa +dig yourcomputer.home.arpa aaaa dig _ssh._tcp.home.arpa ptr dig yourcomputer._ssh._tcp.home.arpa srv ```