mx1.admin.net.pl has no NS records.
NS records for this zone are defined at admin.net.pl.
NS records for this zone are defined at admin.net.pl.
Question and response
Question
dig mx1.admin.net.pl. NS
Answer
The response has no answer records.
Authority
admin.net.pl. 1200 SOA ns1.admin.net.pl. admin.admin.net.pl. 2026130001 10800 3600 604800 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0