mx1.vianet.ca has no NS records.
NS records for this zone are defined at vianet.ca.
NS records for this zone are defined at vianet.ca.
Question and response
Question
dig mx1.vianet.ca. NS
Answer
The response has no answer records.
Authority
vianet.ca. 900 SOA gwn.vianet.ca. hostmaster.vianet.ca. 1772297042 600 900 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0