mail.mutaresoftware.com has no NS records.
NS records for this zone are defined at mutaresoftware.com.
NS records for this zone are defined at mutaresoftware.com.
Question and response
Question
dig mail.mutaresoftware.com. NS
Answer
The response has no answer records.
Authority
mutaresoftware.com. 180 SOA ns10.dnsmadeeasy.com. dns.dnsmadeeasy.com. 2009010141 43200 3600 1209600 180
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0