ns1.sap.net has no NS records.
NS records for this zone are defined at sap.net.
NS records for this zone are defined at sap.net.
Question and response
Question
dig ns1.sap.net. NS
Answer
The response has no answer records.
Authority
sap.net. 172800 SOA ns.sap-ag.de. dns.sap-ag.de. 2025122202 43200 1800 1814400 600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0