smtp064.em4service.cz has no NS records.
NS records for this zone are defined at em4service.cz.
NS records for this zone are defined at em4service.cz.
Question and response
Question
dig smtp064.em4service.cz. NS
Answer
The response has no answer records.
Authority
em4service.cz. 1800 SOA ns1.zcom.cz. hostmaster.zcom.cz. 1774102137 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0