hokuto: update TODO

Author: nyiyui

hokuto/README.md

@@ -7,7 +7,11 @@ Domain format: `<peer-name>.<cn-name>.<parent>` e.g. `desktop.mynet.qrystal.inte
 Returns `A` records per-peers' allowed IPs, and `TXT` records for other metadata.
 
 This DNS server **doesn't** forward unknown DNS requests to some server.
+(This is to keep the program simple.)
+Therefore, you need another DNS server in front of this one that only forwards requests the end in a specific parent (e.g. `.qrystal.internal`).
 
 ## TODO
 
 - Reverse lookups.
+- multiple parents (e.g. `.internal.example.org` and `.qrystal.internal)
+- preset CNs for parents (e.g. `<peer-name>.internal.example.org` (no CN name))