mx10.pbs.edu.pl has no NS records.
NS records for this zone are defined at pbs.edu.pl.
NS records for this zone are defined at pbs.edu.pl.
Question and response
Question
dig mx10.pbs.edu.pl. NS
Answer
The response has no answer records.
Authority
pbs.edu.pl. 900 SOA sun1.utp.edu.pl. please_set_email.absolutely.nowhere. 1341 10800 3600 2419200 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0