smtp.miramo.cz has no NS records.
NS records for this zone are defined at miramo.cz.
NS records for this zone are defined at miramo.cz.
Question and response
Question
dig smtp.miramo.cz. NS
Answer
The response has no answer records.
Authority
miramo.cz. 3600 SOA miramo1.miramo.cz. hostmaster.miramo.cz. 202602090 3600 3600 3600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0