nslookup fails if missing PTR record for IPv6 DNS server.

[Mark Andrews]

Or one can use nslookup from BIND 9 which doesn't have that
restriction.

nslookups with this restriction are at least 10 years old now and
there have been new types added.  DNSSEC has been completely
overhauled in that time.

Mark
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org