spf.siol.net has no CNAME records.
Question and response
Question
dig spf.siol.net. NS
Answer
The response has no answer records.
Authority
siol.net. 300 SOA taurus-1.siol.net. dns.siol.net. 2026021905 28800 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0