What is
SPF?
SPF is a DNS record that specifies which mail servers are authorized to send email on behalf of your domain.
Why it
matters.
SPF prevents email spoofing. Without it, anyone can send emails claiming to be from your domain. The "-all" mechanism is critical - it means "reject all emails from servers not listed", providing strict protection.
What can
go wrong.
If SPF is missing or improperly configured: attackers can spoof emails from your domain, leading to phishing attacks, reputation damage, and email delivery failures. Using "~all" or "?all" instead of "-all" provides weak protection.
Technical
details.
SPF records use mechanisms like: "include:" (authorize other domains), "a" (authorize A records), "mx" (authorize MX records), "ip4:" (authorize specific IPs), "-all" (reject all others - STRICT), "~all" (soft fail - WEAK), "?all" (neutral - NO PROTECTION).
Check your domain’s
SPF record.
Run a free security check to see how your domain scores across all sixteen checks, including SPF validation.