r630.mit.edu has no NS records.
NS records for this zone are defined at mit.edu.
NS records for this zone are defined at mit.edu.
Question and response
Question
dig r630.mit.edu. NS
Answer
The response has no answer records.
Authority
mit.edu. 1800 SOA use2.akam.net. network-request.mit.edu. 22419 900 900 3600000 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0