_netblock2.man.poznan.pl has no NS records.
NS records for this zone are defined at man.poznan.pl.
NS records for this zone are defined at man.poznan.pl.
Question and response
Question
dig _netblock2.man.poznan.pl. NS
Answer
The response has no answer records.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0