vs-prod-exch2013-01.exchange.cornell.edu has no NS records.
NS records for this zone are defined at exchange.cornell.edu.
NS records for this zone are defined at exchange.cornell.edu.
Question and response
Question
dig vs-prod-exch2013-01.exchange.cornell.edu. NS
Answer
The response has no answer records.
Authority
exchange.cornell.edu. 3600 SOA dns.cit.cornell.edu. nsmaster.cornell.edu. 3603271602 1860 600 2592000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0