mail01.megamail.nl has no NS records.
NS records for this zone are defined at megamail.nl.
NS records for this zone are defined at megamail.nl.
Question and response
Question
dig mail01.megamail.nl. NS
Answer
The response has no answer records.
Authority
megamail.nl. 900 SOA ns1.hix.nl. postmaster.megamail.nl. 2013021200 10800 3600 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0