Add troubleshoot section for DNS rebinding
The magic domain won't work with all routers. Entries have to be on the
ok list.
@@ -19,3 +19,13 @@ epinio install
In case of trouble with Epinio's Traefik component or Ingress controllers, the [Traefik](../explanations/advanced.md#traefik) section in the
[Advanced Topics](../explanations/advanced.md) document shall be your friend.
+
+#### DNS Rebind Protection
+
+Some routers filter queries where the answer consists of IP addresses from the private range, like "10.0.0.1".
+
+This stops a malicous website from probing the local network for hosts.
+
+Amongst those routers is the AVM FRITZBox and everything that uses [dnsmasq](https://thekelleys.org.uk/dnsmasq/docs/dnsmasq-man.html) with `stop-dns-rebind`, like [pfSense](https://docs.netgate.com/pfsense/en/latest/services/dns/rebinding.html) or NetworkManager.
+
+If you still want to use the default magic DNS, you'll have to whitelist `omg.howdoi.website` in your local DNS server.
