// REFERENCE
SPF record (in TXT)
Type number: 99*
Sender Policy Framework: lists which servers may send mail on the domain's behalf. It's published as a TXT (v=spf1 …); the dedicated SPF type (99) is deprecated. The foundation against spoofing.
Related tools
Work with this in:
Related
mx
MX record dkim
DKIM record (in TXT) dmarc
DMARC record (in TXT) openpgpkey
OPENPGPKEY record smimea
SMIMEA record
MX record dkim
DKIM record (in TXT) dmarc
DMARC record (in TXT) openpgpkey
OPENPGPKEY record smimea
SMIMEA record
Types per the IANA DNS parameters registry and their RFCs. Educational content.