SPF
From DWIKI
Sites
Docs
- https://dmarcian.com/spf-syntax-table/
- Setting Up SPF, SenderId, Domain Keys, and DKIM
- http://en.wikipedia.org/wiki/Sender_Policy_Framework
- http://homepages.tesco.net/J.deBoynePollard/FGA/smtp-spf-is-harmful.html
- SPF overview
- Why not spf
Tools
- pyspf
- Validate SPF record
FAQ
softfail ~all
A soft fail means that emails from unauthorized senders are not discarded but forwarded to a spam folder, or marked suspicious.
hardfail -all
All other senders—those not listed in the record—are unauthorized, and their emails are discarded.
+all, -all, ~all?
+all
Any server can send
Check SPF record of a host or domain
dig domain.com TXT
or
dig host.domain.com TXT
SPF - Returned fail
Misconfigured SPF record or spoofed "From" address
