swmail05.structuredweb.com has no NS records.
NS records for this zone are defined at structuredweb.com.
NS records for this zone are defined at structuredweb.com.
Question and response
Question
dig swmail05.structuredweb.com. NS
Answer
The response has no answer records.
Authority
structuredweb.com. 900 SOA ns-460.awsdns-57.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0