mx.stable.cz has no NS records.
NS records for this zone are defined at stable.cz.
NS records for this zone are defined at stable.cz.
Question and response
Question
dig mx.stable.cz. NS
Answer
The response has no answer records.
Authority
stable.cz. 3600 SOA ns.stable.cz. hostmaster.stable.cz. 2026021701 32400 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0