mailproxy1.usda.gov has no CNAME records.
Question and response
Question
dig mailproxy1.usda.gov. NS
Answer
The response has no answer records.
Authority
usda.gov. 627 SOA ns1.usda.gov. duty\.officer.usda.gov. 2025496323 90000 9000 90000 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0