we always process them before we process client requests
- DNSSEC
- add display of private key types (http://tools.ietf.org/html/rfc4034#appendix-A.1.1)?
- - DNS
- - search paths
- mDNS/DNS-SD
- mDNS RR resolving
- service registration
- service/domain/types browsing
- avahi compat
- DNS-SD service registration from socket units
- - edns0
- - cname on PTR (?)
- resolved should optionally register additional per-interface LLMNR
names, so that for the container case we can establish the same name
(maybe "host") for referencing the server, everywhere.