pdnsb.hlubina.com has no NS records.
NS records for this zone are defined at hlubina.com.
NS records for this zone are defined at hlubina.com.
Question and response
Question
dig pdnsb.hlubina.com. NS
Answer
The response has no answer records.
Authority
hlubina.com. 1800 SOA ns.gransy.com. root.gransy.com. 2773477069 86400 900 1209600 1800
pdnsb.hlubina.com. 1800 NSEC pdnsc.hlubina.com. A RRSIG NSEC
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0