adns2.ironport.com has no NS records.
NS records for this zone are defined at ironport.com.
NS records for this zone are defined at ironport.com.
Question and response
Question
dig adns2.ironport.com. NS
Answer
The response has no answer records.
Authority
ironport.com. 3600 SOA ns1-93.akam.net. stbu-hostmaster.cisco.com. 2026031002 14400 900 2419200 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0