[Dnsmasq-discuss] Suggestion/Feature Request: Disable only DNS on an interface

[Ryan Zev Solomon]

Good day,

I think it would be useful to disable serving DNS queries on an 
interface on which TFTP, and DHCP are still provided. My use case:
- TFTP and DHCP are provided by Dnsmasq.
- Unbound is used as the DNS recursive resolver/cache.
- Dnsmasq is used as a stub resolver for the addresses handed out via DHCP.

Currently this can be partially achieved by moving Dnsmasq to a 
different port, and blocking that port.

The other option I explored was having Dnsmasq handle the queries 
without caching any of the responses, and using Unbound as the only 
upstream resolver. This was not satisfactory as it prevented the use of 
some of Unbound's more advanced features for the local-only domain which 
Dnsmasq does not offer. In addition, this had a performance hit. (Both 
on AMD64, and MIPS hardware which I tested.)

Motivation:
This would allow one to easily use Dnsmasq for providing DHCP, and easy 
to use network booting with a more fully featured DNS cache (or 
recursive resolver).

Potential issues:
- I haven't a clue as to how interface localised queries would be 
handled. (I don't use that feature myself.)