ironport.ashfed.plateau.com has no NS records.
NS records for this zone are defined at plateau.com.
NS records for this zone are defined at plateau.com.
Question and response
Question
dig ironport.ashfed.plateau.com. NS
Answer
The response has no answer records.
Authority
plateau.com. 300 SOA ns1.sap.net. dns.sap-ag.de. 1774015438 3590 86400 2592000 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0