Using stub-zones to create a "union" local subdomain?

David Madden unbound at
Sat Feb 26 20:54:16 UTC 2022

I have a network with several routed segments; the routers offer WiFi 
connections and assign DHCP addresses.  IP connectivity works fine.

Clients of a single router can reach each other by DNS name because the 
DHCP server (dnsmasq) maintains a local database of assigned names. 
However, clients of router-1 can't resolve names of clients attached to 
router-2 (unless they specifically ask router-2 for the name -- but 
clients generally don't know which router another client is connected to 
at the moment).

All the routers point to an unbound server running at one router for 
their non-local resolution services.

Is there a way to configure unbound to query multiple stub-zone servers 
(the routers) for names in a particular domain?  I can provide multiple 
IPs in a stub-zone configuration block, but if unbound receives an 
NXDOMAIN from one router, it won't proceed to ask the other routers.

What I think would work is a way to disregard NXDOMAIN from stub-zone 
servers.  That way, if a client of r-1 asks for a client of r-2, unbound 
will query r1, r2, r3, ... and if any of them respond with an A record, 
the client can reach its peer.

The alternative of setting up a local dynamic DNS server seems like a 
lot of work for this use case.

Mersenne Law  ·  ·  +1-503-679-1671
Small Business, Startup and Intellectual Property Law
420 N.W. 11th Ave., Suite 814; Portland, Oregon 97209
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