isar.cas.cz has no NS records.
NS records for this zone are defined at cas.cz.
NS records for this zone are defined at cas.cz.
Question and response
Question
dig isar.cas.cz. NS
Answer
The response has no answer records.
Authority
cas.cz. 86400 SOA visla.utia.cas.cz. root.utia.cas.cz. 3568 14400 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0