Troubleshooting “Neutral” SPF Results

When checking email authentication headers, you may notice Received-SPF: neutral instead of the expected pass. An SPF Neutral evaluation means your domain’s SPF record explicitly declined to state whether the connecting server was authorized or unauthorized to send your email. Because it provides zero authentication value, an SPF Neutral result prevents DMARC from passing on the SPF path and leaves your messages vulnerable to spam filtering.

Quick Answer

An SPF “Neutral” result occurs when an email is sent from an IP address that falls through to a ?all (Neutral) qualifier at the end of your DNS TXT record. To fix this, change the trailing mechanism in your SPF record from ?all to ~all (Softfail) or -all (Hardfail).

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What the Neutral Qualifier Means

RFC 7208 defines four distinct qualifiers that can be attached to any mechanism or placed at the end of an SPF record:

Qualifier	Name	Receiver Evaluation	Policy Meaning
+	Pass	pass	The IP address is fully authorized.
-	Fail (Hardfail)	fail	The IP is unauthorized; drop or reject the message.
~	Softfail	softfail	The IP is likely unauthorized; accept but scrutinize.
?	Neutral	neutral	The domain owner explicitly asserts nothing about this IP.

If your domain publishes an SPF string ending with ?all, you are telling receiving servers: “If an email originates from an IP not specifically listed here, I express no opinion on whether it is valid or counterfeit.”

                 [Incoming Message Evaluated]
                              │
               [Receiving Server Checks DNS TXT]
            Record: v=spf1 include:_spf.google.com ?all
                              │
             Does IP match _spf.google.com?
              ┌───────────────┴───────────────┐
             YES                              NO
              │                               │
       Qualifier: [+]                  Qualifier: [?]
       Result: PASS                    Result: NEUTRAL
       (Valid Email)                   (No Assertion Made)
                                              │
                                              ▼
                                   [DMARC SPF Path FAILS]
                                   Relies entirely on DKIM;
                                   Spam score increases.

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Why Administrators Use ?all (and Why It Fails)

The ?all mechanism is frequently deployed by accident:

1. Outdated Setup Wizards: Older DNS configuration wizards often set ?all as a default placeholder to avoid breaking email during initial domain registration.
2. Misunderstanding “Testing Mode”: Administrators sometimes assume ?all is a safe way to test new email vendors. In practice, ~all (Softfail) is the proper mechanism for testing because it allows mail through while signaling intent.
3. Mechanisms with Explicit Question Marks: Placing ? before an IP block or include (e.g., ?include:sendgrid.net) evaluates that specific vendor as Neutral even if the rest of the record ends in ~all.

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How Neutral Impacts DMARC and Deliverability

An SPF Neutral result causes two significant deliverability problems:

1. Immediate DMARC Failure on the SPF Path

DMARC requires an explicit pass combined with identifier alignment. A result of neutral is treated as a non-pass. If the email also lacks a valid, aligned DKIM signature, DMARC validation fails completely. If your DMARC policy is set to p=quarantine or p=reject, the message will be sent to the spam folder or dropped entirely.

2. Spam Filter Skepticism

Modern email providers like Gmail, Yahoo, and Microsoft 365 look for clear authentication signals. Because ?all explicitly refuses to authorize or deny senders, filters treat the message as unverified traffic. This increases the spam penalty score, particularly if sending marketing campaigns or cold communications.

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Diagnostic Steps

Step 1: Verify the Header Output

Check the message headers of a delivered email using How to Read Gmail “Original Message” Headers. Look for the Received-SPF line:

Received-SPF: neutral (google.com: 198.51.100.15 is neither permitted nor denied by domain of example.com) client-ip=198.51.100.15;

This confirms that the IP 198.51.100.15 did not match any authorized mechanism and fell through to a ? qualifier.

Step 2: Inspect Your Live SPF DNS Record

Query your domain’s live TXT record using the command line:

dig example.com TXT +short

Examine the output. Look for:

• A trailing ?all.
• Individual mechanisms prefixed with a question mark (e.g., ?ip4:... or ?include:...).

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Technical Fix: Updating Your Record

To eliminate Neutral results, transition your record to use explicit evaluation qualifiers.

Step 1: Add Any Missing Senders

If the IP reported in your header diagnostic belongs to a legitimate outbound service (such as your CRM, ticketing tool, or website host), add that service’s include: or ip4: mechanism directly into the record. For guidelines on connecting external mailers, see How to Align SPF/DKIM for Third-Party Apps.

Step 2: Replace ?all with ~all or all

Update the TXT record in your DNS zone:

• Change from: v=spf1 include:_spf.google.com ?all
• Change to (Softfail – Recommended during transitions): v=spf1 include:_spf.google.com ~all
• Or Change to (Hardfail – Recommended once all streams are verified): v=spf1 include:_spf.google.com -all

For a detailed breakdown of how mail servers handle the difference between Softfail and Hardfail, read Resolving SPF “Softfail” vs. “Hardfail”.

Step 3: Ensure Only One Record Exists

While updating your record, confirm that your DNS manager does not save the updated string as an additional record. A domain must publish only one SPF string; publishing multiple records triggers an immediate PermError; see Multiple SPF Records Detected (One Record Rule).

Once your new record propagates, re-test using The Workspace Email Authentication Master Checklist to confirm the Received-SPF header updates cleanly to pass.