a.gslb.aaplimg.com has no NS records.
NS records for this zone are defined at gslb.aaplimg.com.
NS records for this zone are defined at gslb.aaplimg.com.
Question and response
Question
dig a.gslb.aaplimg.com. NS
Answer
The response has no answer records.
Authority
gslb.aaplimg.com. 300 SOA ns-ext-prod.jackfruit.apple.com. dnscontact.apple.com. 130 7200 5400 3628800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0