stl.mailproxy1.usda.gov has no CNAME records.
Question and response
Question
dig stl.mailproxy1.usda.gov. NS
Answer
The response has no answer records.
Authority
usda.gov. 900 SOA ns1.usda.gov. duty\.officer.usda.gov. 2025501466 90000 9000 90000 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0