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+# Using Yggdrasil/OpenNIC/YunoHost
+
+This is research on doing "gratis" self-hosting.
+
+* Yggdrasil is an overlay IPv6 network running on top of the Internet.
+  All devices on Yggdrasil have a fixed IP address, no matter where in the Internet they are.
+  The Yggdrasil IP address is reachable by other devices in the Yggdrasil network.
+
+  This means that you do not need any public IP address to communicate between devices on Yggdrasil.
+
+  Therefore, you do not need to pay for public IP addresses, and have some extra flexibility.
+  (You can move a host between networks and you can continue to be reachable without dynamic DNS, etc.)
+
+* OpenNIC is an alternate DNS root.
+  Systems using OpenNIC servers can resolve hostnames on OpenNIC.
+
+  Registering OpenNIC domains has no cost.
+
+  Therefore, you do not need to pay a DNS domain.
+
+* YunoHost provides easy installation of many popular self-hosted services.
+
+## Notes
+
+* The Debian README for Yggdrasil sets up a configuration without public peers.
+  My testing hosts discovered each other only because they were on the same IPv4 network, probably.
+
+* be.libre domains take a while to be operative.
+
+## Caveats
+
+* The OpenNIC ACME service cannot connect to an Yggdrasil host!
+* Do not create an initial user on Debian that matches the username you want on YunoHost!
+* YunoHost seems to override your DNS configuration with a list of public DNS servers (?)
+* The YunoHost firewall also messes with Yggdrasil.
+* The Debian package for Debian 12 is not compatible with public Yggdrasil nodes.
+  The backport is good.
+* At least be.libre only allows A, AAAA, NS, and TXT records.
+  Mail should still work without MX records, in theory.
+* Let's Encrypt does not issue OpenNIC certificates, and the only alternative seems to be an experimental CA that supports ACME.