[dns-operations] is there a diagnostic tool to obtain delegated ns?

[Paul Vixie]

> Is there already any tool specifically outputs the authoritative
> nameservers as they are delegated in the rootzone for a domain?

res_findzonecut(), inside libbind (now called netresolv), provides an
API that does what you don't want (gets the zone's apex NS RRset), but
is implemented with logic you could hack to grab the information you do
want (the closest ancestor's delegation NS RRset), as it goes by.

http://wiki.netbsd.org/individual-software-releases/netresolv/

vixie