Mailchk

Free Tool

SPF Record Checker

Validate your domain's Sender Policy Framework (SPF) configuration. Check if your email authentication is properly set up to prevent spoofing.

What is SPF?

Sender Policy Framework (SPF) is an email authentication protocol that allows domain owners to specify which mail servers are authorized to send email on behalf of their domain. It helps prevent spammers from sending messages with forged "From" addresses at your domain.

How SPF Works

When an email is received, the recipient's mail server looks up the SPF record in the sender's domain DNS. The SPF record is a TXT record that lists all IP addresses and servers permitted to send email for that domain.

The receiving server compares the sending server's IP address against this list. If the IP matches, the SPF check passes. If not, the email may be marked as spam, rejected, or flagged depending on the policy defined in the record.

SPF works alongside DKIM and DMARC to form a complete email authentication framework that protects your domain from phishing and spoofing attacks.

Why SPF Matters

Prevents unauthorized servers from sending email as your domain

Improves email deliverability and inbox placement rates

Protects your brand reputation from phishing attacks

Required by major providers like Google and Microsoft for bulk senders

Common SPF Mechanisms

MechanismDescription
includeAuthorizes another domain's SPF record to send on your behalf
ip4Authorizes a specific IPv4 address or CIDR range
ip6Authorizes a specific IPv6 address or range
mxAuthorizes the domain's MX record hosts to send email
aAuthorizes the domain's A record IP address
-allHard fail: reject email from unauthorized servers
~allSoft fail: accept but mark email from unauthorized servers
+allAllow all servers (not recommended, defeats SPF purpose)

Automate SPF checks with our API

Integrate SPF validation into your workflow. Programmatically check SPF records, monitor changes, and ensure your email authentication stays healthy.