mail1.dodano.cz has no NS records.
NS records for this zone are defined at dodano.cz.
NS records for this zone are defined at dodano.cz.
Question and response
Question
dig mail1.dodano.cz. NS
Answer
The response has no answer records.
Authority
dodano.cz. 900 SOA ns1.houfek.cz. dnsadmin.houfek.cz. 128 900 600 86400 3600
Additional
. 0 OPT ; payload 4000, xrcode 0, version 0, flags 0