--- title: "SPF Record Format: A Complete Guide for DNS Configuration | AutoSPF" description: "Understand the SPF record format - version, mechanisms, qualifiers, and modifiers. Learn how to structure your SPF TXT record for proper email authentication." image: "https://autospf.com/images/og-default.png" canonical: "https://autospf.com/spf-record-format/" --- Complete Reference # SPF Record Format A complete reference guide to the Sender Policy Framework record format - mechanisms, qualifiers, modifiers, and real-world examples. RFC 7208 compliant Record Structure ## Anatomy of an SPF Record `v=spf1 ip4:192.0.2.1 include:_spf.google.com -all` v=spf1 Version ip4:192.0.2.1 Mechanism include:... Mechanism \-all Qualifier + Catch-all Building Blocks ## Mechanisms Mechanisms define which servers are authorized to send email on behalf of your domain. Each mechanism counts toward the 10-DNS-lookup limit (except `ip4`, `ip6`, and `all`). | Mechanism | Example | Description | DNS Lookup? | | --------- | --------------------------- | --------------------------------------------------------------- | ----------- | | ip4 | ip4:192.0.2.0/24 | Authorize a specific IPv4 address or CIDR range | No | | ip6 | ip6:2001:db8::/32 | Authorize a specific IPv6 address or range | No | | a | a | Authorize the domain's A record IP addresses | Yes | | mx | mx | Authorize the domain's MX record mail servers | Yes | | include | include:\_spf.google.com | Reference another domain's SPF record | Yes | | all | \-all | Catch-all mechanism - matches everything not previously matched | No | | exists | exists:%{i}.spf.example.com | Check if a DNS A record exists (used in SPF macros) | Yes | | ptr | ptr | Reverse DNS check (deprecated - do not use) | Yes | Action Types ## Qualifiers Qualifiers are prefixed to mechanisms and tell the receiving server what action to take when a match occurs. If no qualifier is specified, `+` (Pass) is the default. + ### Pass Accept the email. The sender is authorized. \- ### Fail Reject the email. The sender is not authorized. \~ ### Soft Fail Accept but mark as suspicious. Use during testing. ? ### Neutral No assertion. Treat as if there is no SPF policy. Advanced Options ## Modifiers ### redirect= Directs SPF processing to another domain's SPF record. Replaces the current domain's policy entirely. `v=spf1 redirect=_spf.example.com` ### exp= Provides a custom explanation message when an SPF check fails. Useful for diagnostics. `v=spf1 ... -all exp=explain._spf.example.com` Real-World Examples ## Common SPF Record Examples ### Basic - Single IP `v=spf1 ip4:192.0.2.1 -all` ### Google Workspace + Your Server `v=spf1 ip4:192.0.2.1 include:_spf.google.com -all` ### Google + Microsoft 365 `v=spf1 include:_spf.google.com include:spf.protection.outlook.com -all` ### A + MX Records with Soft Fail `v=spf1 a mx include:_spf.google.com ~all` Recommended Practices ## Best Practices - Never use `+all` \- it authorizes every server on the internet - Keep DNS lookups under 10 - use SPF flattening if needed - Regularly review and update your SPF record when changing email providers - Test your record after every change with an SPF checker tool - Avoid the deprecated `ptr` mechanism - Prefer `-all` (hard fail) over `~all` once you've verified all sending sources ## Don't manage SPF records manually AutoSPF automatically flattens and optimizes your SPF record format. Setup takes 60 seconds. [Start Free Trial→](https://app.autospf.com/login)[View Plans & Pricing](/pricing/) Rated 5/5 on G2 · Trusted since 2018 ## What Our Customers Say ### "AutoSPF Flattens SPF Records Seamlessly & Keeps Changes Logged - I am quite pleased with the product" > It does what it promises to do, and does it very well. I appreciate that it keeps a log of changes made, which prevents many mistakes. A client's SPF record would have way too many lookups, but AutoSPF makes that problem go away. The length of the SPF record is typically not the issue; it's the amount of lookups in the record that are. AutoSPF "flattens" the record, automatically expanding the defined lookups to IP addresses or ranges. And it auto-updates the record when the un-flattened lookups change. PJ Peter J. President · Small-Business (50 or fewer emp.) ### "Helped us go beyond capacity" > AutoSPF did exactly as described, it helped us get past our 10 lookup limit. Afterwards, we hit another limit regarding overall capacity and when contacted, they quickly provided us with a new solution to eliminate capacity issues entirely going forward, so now we can add as many SPF records as needed. They also provided us with a personalized support video explaining their new method in its entirety using our instance as the example. VU Verified User Financial Services · Mid-Market (51-1000 emp.) [Read our reviews on G2 ](https://www.g2.com/products/autospf/reviews) ```json {"@context":"https://schema.org","@type":"Organization","@id":"https://www.wikidata.org/wiki/Q138897474","name":"AutoSPF","url":"https://autospf.com","logo":{"@type":"ImageObject","url":"https://autospf.com/images/autospf-logo.png"},"description":"Automatic SPF flattening and email authentication management. 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I appreciate that it keeps a log of changes made, which prevents many mistakes. A client's SPF record would have way too many lookups, but AutoSPF makes that problem go away. The length of the SPF record is typically not the issue; it's the amount of lookups in the record that are. AutoSPF \"flattens\" the record, automatically expanding the defined lookups to IP addresses or ranges. And it auto-updates the record when the un-flattened lookups change.","name":"AutoSPF Flattens SPF Records Seamlessly & Keeps Changes Logged - I am quite pleased with the product","publisher":{"@type":"Organization","name":"G2","url":"https://www.g2.com"}},{"@type":"Review","reviewRating":{"@type":"Rating","ratingValue":5,"bestRating":5},"author":{"@type":"Person","name":"Verified User","jobTitle":"Financial Services"},"datePublished":"2025-07-31","reviewBody":"AutoSPF did exactly as described, it helped us get past our 10 lookup limit. 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