smtpcom18.aruba.it has no CNAME records.
Question and response
Question
dig smtpcom18.aruba.it. NS
Answer
The response has no answer records.
Authority
aruba.it. 600 SOA arudns1.aruba.it. hostmaster.aruba.it. 2026030307 86400 7200 2592000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0