[NZLUG] Friday finking: DNS 'map'

Martin D Kealey martin at kurahaupo.gen.nz
Sun Jan 18 01:22:48 NZDT 2015


On Fri, 16 Jan 2015, DL Neil wrote:
> what I would like is something like: (maybe think traceroute...)
>
> 0 127.0.0.1 hosts file - not found - referring to DNS
> 1 192.168.1.251 - not found - forwarding
> 2 192.168.1.1 - not found - forwarding
> 3 208.67.220.220 - success

Hi David

This appears to describe a putative behaviour of the local stub resolver on
your host; if such a tool exists, it would be coupled to the stub resolver,
rather than part of any DNS server-side tools.

Otherwise you could simply scan for and capture DNS packets on the wire,
either on the host or on the router.

Having said that, most host-based (stub) resolvers only use ONE forwarding
resolver; and of those which support more than one, if the first one says
NXDOMAIN then that's it, no other DNS servers are queried.

-Martin


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