mx.metronet.cz has no NS records.
NS records for this zone are defined at metronet.cz.
NS records for this zone are defined at metronet.cz.
Question and response
Question
dig mx.metronet.cz. NS
Answer
The response has no answer records.
Authority
metronet.cz. 360 SOA ns1.metronet.cz. hostmaster.metronet.cz. 2026020416 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1680, xrcode 0, version 0, flags 0