SPF Qualifiers

What are SPF Qualifiers?

SPF qualifiers define how each mechanism in a Sender Policy Framework (SPF) record influences the outcome of an email authentication check. They determine whether a particular match should pass, fail, or be treated as neutral. Qualifiers act as control flags that help receiving mail servers interpret the sender’s intent for each rule in the SPF record.

Each mechanism in an SPF record may include one of four qualifiers. These symbols appear immediately before the mechanism and modify how it is evaluated by the receiving server. When omitted, the default qualifier is “+” (Pass).

How SPF Qualifiers Work

SPF qualifiers and their meanings:

• + (Pass) – The host is authorized to send email for the domain.
• - (Fail) – The host is not authorized; the message should be rejected.
• ~ (SoftFail) – The host is probably not authorized; the message may be accepted but marked as suspicious.
• ? (Neutral) – No policy is stated; the result is inconclusive.

Example SPF record using qualifiers:

In this example, the -all qualifier enforces a strict policy by rejecting messages from all IP addresses not explicitly listed. Replacing it with ~all would allow those messages through but tag them as potential spam instead.

Best Practices for SPF Qualifiers

Choosing the right qualifier is essential for balancing security and deliverability. Overly strict rules can block legitimate mail, while lenient ones leave a domain exposed to spoofing. Administrators typically begin with ~all during testing, then progress to -all once legitimate sources are verified.

• Use ~all while validating all sending IPs
• Switch to -all for full protection after verification
• Avoid ? unless troubleshooting authentication results
• Keep the record within the SPF query limit to avoid lookup failures

SPF Qualifiers and DMARCeye

DMARCeye continuously analyzes SPF records across your domain infrastructure, highlighting how each qualifier impacts mail flow and authentication results. By correlating qualifiers with DMARC aggregate data, the platform helps identify over-permissive or inconsistent policies that could weaken security.

Through visual insights, DMARCeye makes it easy to fine-tune SPF qualifiers so that enforcement aligns perfectly with organizational intent, maximizing both deliverability and protection.

Sign up for a free trial of DMARCeye today and secure your email domain.

To learn more about DMARC and DMARC-related terms, explore the DMARCeye Glossary.