esmtp4.gts.sk has no NS records.
NS records for this zone are defined at gts.sk.
NS records for this zone are defined at gts.sk.
Question and response
Question
dig esmtp4.gts.sk. NS
Answer
The response has no answer records.
Authority
gts.sk. 900 SOA ns.nextra.sk. hostmaster.nextra.sk. 2026021901 21600 7200 1209600 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0