[dns-operations] debug tool to generate DNS response?

[Paul Hoffman]

On 27 Jan 2018, at 10:31, Yang Yu wrote:

> I am looking for a DNS server/debug tool that can respond to selected
> queries with a crafted (potentially broken) response, like BadSSL for
> DNS. Ideally all flags/codes should be customizable. This is quite
> helpful for testing DNS clients.
>
> For example, aaaa-servfail.example.org returns NoError for A but
> ServFail for AAAA.

There are a bunch of such tools. CoreDNS (https://coredns.io/) seems 
pretty flexible and easy to use.

--Paul Hoffman