mail.infra01.awk.jp has no CNAME records.
Question and response
Question
dig mail.infra01.awk.jp. NS
Answer
The response has no answer records.
Authority
infra01.awk.jp. 2738 SOA ns.infra01.awk.jp. takuto\.nakamura.nhn-techorus.com. 2026010817 14400 60 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0