Hostname Discovery

[Havard Eidnes]

> What is typically used to auto discover Hostnames with Unbound
> and NSD? I have an Unbound server pointing to an NSD server for
> local domain Authoritative queries.  Which works brilliantly.
> What method, tool, etc is used to autodiscover hostnames so
> don't need to manually add them to NSD?

Your question comes pretty close to asking "how can I use the DNS
without doing DNS".

That said, there are probably two main avenues you could follow
to get closer to what I think you are asking for.  I should
probably also mention that I do not have own practical experience
with either of them:

1) Use dynamic DNS updates.  Probably requies quite a bit of setup,
   e.g. you need a publishing DNS server which is configured to
   authorize DDNS updates, and possibly some configuration on your
   DHCP server or participating hosts.  I think configured correctly,
   hosts can be allowed to register their own preferred hostname,
   either directly or the DHCP server does it on their behalf on
   address assignment.  I have not looked into whether NSD supports
   DDNS, but from what I saw of it before, "maybe not".  I know that
   BIND does, though.

2) Use MDNS, which is "multicast DNS", and which I think doesn't use
   the hierarchical delegation model of the global DNS, but uses at
   least parts of the DNS protocol to allow for hosts on a LAN to chat
   multicast DNS to each other and have the ability to respond when
   their own preferred hostname is looked up by another host.  You may
   have to tweak /etc/nsswitch.conf or corresponding to enable this
   protocol, and may also need to run mdnsd (or whatever corresponds
   to that).  The MDNS protocol has its origin with Apple, but is also
   defined in RFCs on the standards track.  See
   http://www.multicastdns.org/ for more information.

Good luck,

- Håvard