dns4.datacenters.net has no NS records.
NS records for this zone are defined at datacenters.net.
NS records for this zone are defined at datacenters.net.
Question and response
Question
dig dns4.datacenters.net. NS
Answer
The response has no answer records.
Authority
datacenters.net. 3600 SOA dns1.datacenters.net. dns.datacenters.net. 2026030901 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0