mx.cgp.vtr.net has no NS records.
NS records for this zone are defined at cgp.vtr.net.
NS records for this zone are defined at cgp.vtr.net.
Question and response
Question
dig adxironvtr.vtr.com. NS
Answer
The response has no answer records.
Authority
vtr.com. 300 SOA ns00.vtr.net. hostmaster.vtr.net. 2025112002 10800 3600 604800 38400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0