srvmx.cyfronet.pl has no NS records.
NS records for this zone are defined at cyfronet.pl.
NS records for this zone are defined at cyfronet.pl.
Question and response
Question
dig srvmx.cyfronet.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