mail2.servicioatt.com.mx has no NS records.
NS records for this zone are defined at servicioatt.com.mx.
NS records for this zone are defined at servicioatt.com.mx.
Question and response
Question
dig mail2.servicioatt.com.mx. NS
Answer
The response has no answer records.
Authority
servicioatt.com.mx. 3600 SOA dns.alestra.net.mx. soporteip.axtel.com.mx. 762215068 10800 3600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0