ZeroNS: a name service centered around the ZeroTier Central API

ZeroNS provides names that are a part of ZeroTier Central's configured networks; once provided a network it:

• Listens on the local interface joined to that network -- you will want to start one ZeroNS per ZeroTier network.
• Provides general DNS by forwarding all queries to /etc/resolv.conf resolvers that do not match the TLD, similar to dnsmasq.
• Tells Central to point all clients that have the "Manage DNS" settings turned on to resolve to it.
• Finally, sets a provided TLD (.domain is the default), as well as configuring A (IPv4) and AAAA (IPv6) records for:
  • Member IDs: zt-<memberid>.<tld> will resolve to the IPv4/v6 addresses for them.
  • Names: if the names are compatible with DNS names, they will be converted as such: to <name>.<tld>.
    • Please note that collisions are possible and that it's up to the admin to prevent them.

Installation

Please obtain a working rust environment first.

cargo install --git https://github.com/zerotier/zeronsd --branch main

Usage

Setting ZEROTIER_CENTRAL_TOKEN in the environment is required. You must be able to administer the network to use zeronsd with it. Also, running as root is required as many client resolvers do not work over anything but port 53. Your zeronsd instance will listen on both udp and tcp, port 53.

Tip: running sudo? Pass the -E flag to import your current shell's environment, making it easier to add the ZEROTIER_CENTRAL_TOKEN.

zeronsd start <network id>

You must have already joined a network and obviously, zerotier-one should be running!

It should print some diagnostics after it has talked to your zerotier-one instance to figure out what IP to listen on. After that it should communicate with the central API and set everything else up automatically.

Flags

• -d <tld> will set a TLD for your records; the default is domain.
• -f <hosts file> will parse a file in /etc/hosts format and append it to your records.
• -s <secret file> path to authtoken.secret which is needed to talk to ZeroTier on localhost. You can provide this file with this argument, but it is auto-detected on multiple platforms including Linux, OS X and Windows.
• -t <central token file> path to file containing your ZeroTier Central token.

TTLs

Records currently have a TTL of 60s, and Central's records are refreshed every 30s through the API. I felt this was a safer bet than letting timeouts happen.

Acknowledgements

ZeroNS demands a lot out of the trust-dns toolkit and I personally am grateful such a library suite exists. It made my job very easy.

Author

Erik Hollensbe github@hollensbe.org