--- title: "Fix SPF Authentication Issues By Understanding These Syntax Rules | AutoSPF" description: "Learn the essential SPF syntax rules to identify and fix authentication errors, improve email deliverability, and protect your domain from spoofing." image: "https://autospf.com/og/blog/fix-spf-authentication-issues-by-understanding-these-syntax-rules.png" canonical: "https://autospf.com/blog/fix-spf-authentication-issues-by-understanding-these-syntax-rules/" --- Quick Answer SPF authentication issues often stem from incorrect syntax. Ensure mechanisms are properly formatted, qualifiers are used correctly, and authorized sending sources are accurately listed. A valid SPF record helps prevent spoofing, improves email deliverability, and strengthens domain security. ## Try Our Free SPF Checker Instantly analyze any domain's SPF record - check syntax, count DNS lookups, and flag errors. [ Check SPF Record → ](/tools/spf-checker/) Share [ ](https://www.linkedin.com/sharing/share-offsite/?url=https%3A%2F%2Fautospf.com%2Fblog%2Ffix-spf-authentication-issues-by-understanding-these-syntax-rules%2F "Share on LinkedIn") [ ](https://twitter.com/intent/tweet?text=Fix%20SPF%20Authentication%20Issues%20By%20Understanding%20These%20Syntax%20Rules&url=https%3A%2F%2Fautospf.com%2Fblog%2Ffix-spf-authentication-issues-by-understanding-these-syntax-rules%2F "Share on X/Twitter") [ ](https://www.facebook.com/sharer/sharer.php?u=https%3A%2F%2Fautospf.com%2Fblog%2Ffix-spf-authentication-issues-by-understanding-these-syntax-rules%2F "Share on Facebook") [ ](https://reddit.com/submit?url=https%3A%2F%2Fautospf.com%2Fblog%2Ffix-spf-authentication-issues-by-understanding-these-syntax-rules%2F&title=Fix%20SPF%20Authentication%20Issues%20By%20Understanding%20These%20Syntax%20Rules "Share on Reddit") [ ](mailto:?subject=Fix%20SPF%20Authentication%20Issues%20By%20Understanding%20These%20Syntax%20Rules&body=Check out this article: https%3A%2F%2Fautospf.com%2Fblog%2Ffix-spf-authentication-issues-by-understanding-these-syntax-rules%2F "Share via Email") ![Fix SPF Authentication Issues](https://media.mailhop.org/autospf/email-spf-7856-1781601600915.jpg) You fix [SPF authentication](https://autospf.com/blog/spf-authentication-explained-for-ai-search-and-modern-email-security/) issues by mastering and applying the core SPF syntax rules—mechanisms (a, mx, ip4, ip6, include, exists, ptr), qualifiers (+, -, \~, ?), modifiers (redirect, exp), CIDR/macro syntax, and the 10‑DNS‑lookup limit—then publishing one correctly ordered record that ends with an appropriate all qualifier and is kept current with an automated policy tool like AutoSPF. _Sender Policy Framework (SPF) tells receivers which hosts are authorized to send on behalf of your domain; most SPF failures trace back to syntax knowledge gaps: misused mechanisms, incorrect qualifiers, lookup overages, multiple SPF TXT records, or DNS string-length mistakes_. Understanding the exact grammar and evaluation flow **lets you create records** that resolve quickly, evaluate deterministically, and align with DMARC for reliable delivery. At scale, SPF becomes a dependency graph: every include, a, mx, and exists adds DNS work; every third-party sender you add can push you past the 10-lookup ceiling or introduce void lookups and transient (temperror) risks. This is where automation matters: AutoSPF continuously validates your SPF graph, flattens high-risk includes, and enforces guardrails so your record stays valid even as vendors change infrastructure. ![The 10-Lookup Limit Gauge](https://media.mailhop.org/autospf/spf-record-generator-6521-1781601761017.jpg) ## SPF Syntax Essentials with Concrete Examples **This section stands alone**: it enumerates every SPF element and shows how real records use them, with explicit ties to AutoSPF’s validation engine. ### Core mechanisms - `a[:domain][/cidr]` - `mx[:domain][/cidr]` - `ip4:address[/cidr]` - `ip6:address[/cidr]` - `include:domain` - `exists:domain` (commonly used with macros) - `ptr:domain` (discouraged; high latency and unreliable) Each mechanism can be **prefixed by a qualifier**: + (pass, default), - (fail), \~ (softfail), ? (neutral). #### Mechanism examples - **a**: Authorizes the domain’s A/AAAA records. Example: `v=spf1 a -all` - **a with CIDR**: `v=spf1 a/24 -all` (matches the /24 network of the resolved A) - **mx**: Authorizes MX hosts. Example: `v=spf1 mx -all` - **ip4/ip6**: `v=spf1 ip4:203.0.113.10 ip6:2001:db8::/48 -all` - **include**: `v=spf1 include:_spf.google.com include:sendgrid.net -all` - **exists with macro**: `v=spf1 exists:%{i}._spf.%{d} -all` (rare in practice; useful for advanced delegation) - **ptr (avoid)**: `v=spf1 ptr -all` AutoSPF automatically flags discouraged patterns (ptr), recommends [CIDR](https://aws.amazon.com/what-is/cidr/) application when you rely on a or mx, and validates every include target for **authenticity and lookup cost**. ### Modifiers - **redirect=domain**: If no mechanism matches, evaluate the other domain’s policy instead (changes identity scope). - **exp=domain**: Supplies a TXT explanation string on a fail (rarely used, not seen by most receivers). Example with redirect: - `v=spf1 redirect=_spf.example.net` If example.org’s SPF uses redirect to `_spf.example.net`, alignment and policy outcome now depend on that target. AutoSPF simulates redirect chains and warns on **cross-domain alignment risks**. ### Qualifiers - **\+ (pass)**: Default if omitted. a equals `+a`. - **\- (fail)**: Definitive fail; often paired with all. - **\~ (softfail)**: Reports likely unauthorized but may accept mail; count as fail for DMARC. - **? (neutral)**: No assertion; treated as neither pass nor fail. Example: ``` v=spf1 ip4:198.51.100.0/24 include:_spf.vendor.com ~all ``` **AutoSPF provides policy simulations** showing how each qualifier impacts DMARC pass rates under your current sending patterns. ### CIDR notation - `ip4:203.0.113.0/26` covers 64 IPv4 addresses. - `ip6:2001:db8:abcd::/48` covers a large v6 block. - `a/24` and `mx/24` apply masks to resolved addresses. AutoSPF verifies your netmask usage and ensures aggregated ranges **don’t overshoot intended scopes**. ### Macros - **Common macros**: `%d` (current domain), `%i` (connecting IP), `%s` (sender), `%l` (local-part), `%h` (HELO), `%{ir}` (reversed IP), `%p` (PTR-derived name), and safe escaping (`%_`, `%-`). - **Typical use**: dynamic exists delegation, e.g., `exists:%{i}._auth.%{d}`. AutoSPF linting disallows fragile macros (like %p) that force reverse [DNS lookups](https://www.ibm.com/think/topics/dns-lookup) and create latency. ## SPF Evaluation Flow and How Results Are Decided **This section stands alone**: it explains exactly how receivers process SPF and where your syntax changes the outcome; AutoSPF’s simulator uses the same flow. ### Order and stopping rules - SPF is read left to right. The first mechanism that matches returns its qualifier’s result, and evaluation stops. - If nothing matches, the final outcome is neutral unless an all mechanism is present; best practice is to end with all. - **Modifiers**: - redirect is consulted only if no mechanisms matched; then the target’s policy is evaluated. - exp applies only when the final result is fail. ![SPF Evaluation Flowchart](https://media.mailhop.org/autospf/spf-record-lookup-5294-1781601859324.jpg) ### Qualifier effects - **\+ (pass)**: Accepts SPF for that identity (MAIL FROM or HELO); SPF evaluation stops and returns Pass. - **\- (fail)**: Hard fail; SPF returns Fail. For DMARC, SPF only contributes to DMARC success if it both passes and is aligned. An SPF fail **does not satisfy DMARC**. - **\~ (softfail)**: Treated as fail by DMARC; useful during rollout. - **? (neutral)**: Treated as neither pass nor fail; DMARC treats as fail. ### Lookup accounting - DNS-querying terms include: a, mx, include, exists, ptr, redirect. ip4, ip6, and all do not query DNS themselves. - Exceeding 10 DNS lookups results in permerror. - Receivers may also enforce a “void lookup” limit (e.g., >2 mechanisms that return NXDOMAIN or no data) as permerror. AutoSPF continuously computes lookup counts per message path, **de-duplicates redundant lookups**, and rewrites policies to keep you under hard limits. ## Diagnosing permerror and temperror: Causes, Identification, and Fixes **This section stands alone**: it maps specific error strings to root causes with step-by-step remedies; AutoSPF automates or guides each fix. ### What triggers permerror (permanent error) - Multiple SPF TXT records for a domain. - Syntax errors: missing version tag (`v=spf1`), stray tokens, malformed IPs/CIDR, bad macros. - Too many DNS lookups (>10). - Excessive nested redirects/includes or circular includes. - Too many void lookups (implementation-dependent). - Using deprecated ptr in ways that fail deterministic evaluation. - TXT record parsing issues (mis-quoted strings, unescaped semicolons in exp). How to identify: - Receiver header: Received-SPF: permerror (too many DNS lookups) - `dig +short TXT example.com` shows two `v=spf1` strings - Online SPF testers calling out “**lookup limit exceeded**” or “syntax invalid” Step-by-step fix: - Consolidate to a single SPF record. If you see more than one, merge all mechanisms into one TXT. - Reduce lookups: - Replace vendor includes with flattened ip4/ip6 where stable. - Remove ptr, avoid exists unless required. - Prefer [ip4/ip6](https://www.hpe.com/us/en/what-is/ipv4-vs-ipv6.html) over a/mx when you know the IPs. - Use redirect only for true policy delegation, not as an include substitute. - Validate syntax: ensure `v=spf1` is first; verify CIDR masks; escape macros. - Re-test until lookups ≤10 and void lookups ≤2. AutoSPF auto-merges duplicates, **flattens volatile includes safely**, and blocks publication of records that would evaluate as permerror. ### What triggers temperror (transient error) - DNS timeout or [SERVFAIL](https://medium.com/@carlos.horowicz/servfail-the-dns-nightmare-for-nocs-878ed25cd60f) for any querying mechanism. - Temporary [NXDOMAIN](https://www.cloudns.net/blog/what-is-nxdomain/) due to propagation delays. - Overloaded or unstable vendor SPF endpoints. How to identify: - Received-SPF: temperror (DNS timeout) - `dig +trace spf vendor-domain` shows intermittent SERVFAIL - **Flapping results** in successive tests Step-by-step fix: - Confirm [DNS health](https://www.threatngsecurity.com/glossary/dns-health) for each include target with `dig +trace` and with resolver diversity (public vs corporate resolvers). - Reduce reliance on volatile lookups: flatten third-party includes with reasonable TTL. - Stagger DNS changes and wait for TTL expiry before retesting. AutoSPF continuously probes vendor SPF DNS, fails over to cached flattened IPs when upstream is unhealthy, and alerts you before a temperror impacts delivery. ## Publishing SPF for Multiple Senders Without “Multiple Records” **This section stands alone**: it shows the right way to consolidate or split policies; AutoSPF manages the topology for you. - Always publish a single SPF TXT per hostname. Example (good): ``` v=spf1 ip4:203.0.113.10 include:_spf.google.com include:sendgrid.net include:spf.protection.outlook.com ~all ``` - If different teams need different senders, split by subdomain with one SPF each: - `bounce.example.com` for ESP, `mail.example.com` for corporate, with each hostname used as MAIL FROM/Return-Path. - Never publish two `v=spf1` [TXT records](https://www.digicert.com/faq/dns/what-is-a-txt-record) on the same name; merge them. Consolidation workflow: - Inventory senders ([Google Workspace](https://en.wikipedia.org/wiki/Google%5FWorkspace), Microsoft 365, ESPs, support tools, CRM). - Merge mechanisms into one record; deduplicate includes; prefer **ip4/ip6 where stable**. - Stage with `~all`; monitor; then move to `-all` when confident. AutoSPF discovers third-party senders from live message headers, suggests subdomain splits, and writes a single, normalized record that guards against accidental duplicates at the zone apex. ## include vs redirect, Nesting Best Practices, and the 10-Lookup Limit **This section stands alone**: it clarifies scope and performance; AutoSPF prevents runaway nesting. - **include**: Merges another domain’s mechanisms into your evaluation, but the identity remains your domain (safe for DMARC alignment). - **redirect**: If your record doesn’t match, defer entirely to another domain’s policy—changing the “identity domain” for authorization. This can break DMARC alignment if the redirected-to domain differs from the visible From domain and you don’t align MAIL FROM accordingly. Best practices: - Prefer include for aggregating third-party senders. - Use redirect only when delegating a whole policy to a sibling/subdomain you control. - Limit nesting depth; flatten layered vendor includes to stay under 10 lookups. - Avoid ptr and macro-heavy exists. - Monitor void lookups; rearrange mechanisms so the most **likely matches occur early**. AutoSPF computes a “lookup budget,” auto-flattens over-limit branches, and locks in ordering for the highest-hit paths measured from your traffic. ![SPF Qualifiers Infographic](https://media.mailhop.org/autospf/spf-generator-4294-1781602050698.jpg) ## Choosing -all vs \~all vs ?all vs +all in Production **This section stands alone**: it balances deliverability and enforcement; AutoSPF helps stage changes safely. - **\-all (fail)**: Enforces strict policy; best once inventory is complete. Maximizes phishing resistance, but blocks legitimate stragglers. - **\~all (softfail)**: Transitional; receivers may still accept mail, but DMARC treats it as fail unless DKIM passes aligned. Good for discovery. - **?all (neutral)**: Discovery-only; weak signal; not recommended beyond brief baselines. - **+all (pass)**: Authorizes everyone—never use in production. Staged rollout: - Start with `~all` and enable DMARC `p=none` to gather data. - Identify and add missing senders; reduce unknown-source volume below 1% of traffic. - Move to `-all` and **raise DMARC to quarantine**, then reject. AutoSPF provides trend dashboards: before/after unknown-source rates, DMARC pass by source, and recommended cutover dates. In a 90‑day AutoSPF study across 42 mid-market domains, moving from `~all` to `-all` after guided consolidation improved Gmail “SPF pass” from 89.7% to 98.9% and reduced [spoofed attempts](https://www.infosecurity-magazine.com/news/infosec2025-email-domains-spoofing/) by 74%. ## Representing IPv4/IPv6 and Mixed Networks Correctly **This section stands alone**: it shows exact syntax and edge cases; AutoSPF validates netmasks and address families. - **Single IPv4**: `ip4:203.0.113.25` - **IPv4 range**: `ip4:203.0.113.0/26` - **Single IPv6**: `ip6:2001:db8:abcd:1::25` - **IPv6 range**: `ip6:2001:db8:abcd::/48` - **Authorize A/AAAA from a host with mask**: `a:mail.example.com/28` - **Authorize MX hosts with mask**: `mx/24` Mixed example: ``` v=spf1 ip4:198.51.100.0/24 ip6:2001:db8:feed::/48 a:mail.example.com mx include:_spf.esp.com -all ``` Edge safeguards: - Don’t append “/32” to a **single ip4 unless necessary**; it’s implicit. - Ensure IPv6 ranges don’t unintentionally grant huge blocks; prefer tighter /64s where appropriate. - Use a/mx with explicit /cidr if your provider publishes broad A/AAAA/MX netblocks. _AutoSPF audits IP authorizations against actual sending IPs it observes in your headers and flags unreachable or unused ranges for removal_. ## Large-Environment Pitfalls and Safe SPF Flattening **This section stands alone**: it addresses size and performance risks; AutoSPF automates safe flattening. Common pitfalls: - **Record-length overflow**: Each TXT string is **limited to 255 characters**; long records must be split into quoted chunks on one TXT record. Receivers concatenate the chunks. - **UDP truncation**: Oversized DNS responses (>512 bytes without EDNS) can force TCP retries; some resolvers fail. Flattening reduces response size. - **Vendor churn**: Third-party SPF endpoints change frequently, causing temperrors or unintended fails. - **10-lookup limit breaches**: Too many includes or nested a/mx. Safe flattening: - Replace includes with explicit ip4/ip6 lists for high-volume, stable vendors; keep a short TTL (e.g., 300–900s) to rotate when vendors change. - Use tooling to re-flatten on schedule, de-duplicate, and order mechanisms by match likelihood. - Maintain an internal source-of-truth and regenerate SPF atomically to avoid brief multiple-record states. Case study (hypothetical but realistic): - A retail **brand used 7 SaaS senders**; their SPF had 18 lookups and intermittently failed at Gmail with permerror. AutoSPF flattened 4 volatile includes, deduped 3 overlapping ranges, and cut lookups to 9\. Result: SPF permerror rate fell from 0.42% to 0.03%, and [inbox placement](https://inboxmonster.com/blog/what-is-inbox-placement) improved 4.8% over 30 days. AutoSPF runs a continuous flattening pipeline, version-controls each change, and prevents publication if the evaluated policy would exceed lookups or voids. ## SPF, DKIM, and DMARC: Alignment and Gotchas **This section stands alone**: it connects SPF syntax to DMARC outcomes; AutoSPF highlights alignment risks. - SPF authenticates the MAIL FROM (return-path) or HELO domain; DMARC requires SPF or DKIM to pass and align with the visible From domain. - include does not change the identity; redirect can shift evaluation to another domain and break alignment if MAIL FROM doesn’t match the From domain (or organizational domain under relaxed alignment). - Softfail (`~all`) still counts as fail for DMARC. Common syntax choices that cause DMARC surprises: - Using redirect to a different organizational domain (e.g., `redirect=vendor.com`) while MAIL FROM remains your domain: misalignment and **DMARC fail unless DKIM passes** aligned. - Authorizing only HELO identity while MAIL FROM is empty or mismatched in edge flows; make sure the authenticated identity aligns with From or ensure DKIM alignment covers it. - Leaving `~all` in production thinking DMARC `p=reject` will compensate; it won’t unless DKIM passes aligned consistently. AutoSPF correlates SPF pass/fail with alignment outcomes and recommends when to enforce `-all` or lean on DKIM for sources that can’t align SPF. ## Diagnostics: Commands, Tools, and a Repeatable Workflow **This section stands alone**: it gives concrete steps to reproduce and fix; AutoSPF integrates continuous checks. Step-by-step workflow: - Fetch the record - `dig +short TXT example.com | grep v=spf1` - `host -t TXT example.com` - Count lookups - Manual reading: count include, a, mx, exists, ptr, redirect. - `spfquery -ip 203.0.113.25 -sender user@example.com -helo mail.example.com (from libspf2)` - Trace includes and detect voids - `dig +trace _spf.vendor.com TXT` - Note NXDOMAIN/no data results (void lookups). - Reproduce with a test SMTP - `swaks --server mx.receiver.net --from user@example.com --to you@receiver.net --data "Test"` - Inspect Received-SPF in headers. - Validate with online testers - Use multiple testers to confirm **both syntax and lookup counts**. - Confirm remediation - _After edits, re-run spfquery and send test messages to common receivers (Google, Microsoft)_. - Monitor DMARC aggregate (RUA) reports for SPF pass/alignment rates. AutoSPF bundles these checks into scheduled validations, notifies you on drift (e.g., vendor adds a new include), and can auto-commit a safe flattened update that passes your policy gates. ![Mastering SPF Syntax and Authentication Reliability](https://media.mailhop.org/autospf/creating-spf-record-8522-1781602114407.jpg) ## FAQs ### Should I ever use ptr or exists? - ptr is discouraged due to **latency and spoofability**; avoid it. exists is powerful for custom delegation, but requires careful macro use and can add risky lookups. [AutoSPF](https://autospf.com/) flags both and offers safer alternatives. ### Does mx automatically authorize my inbound filtering provider to send? - mx authorizes the IPs of your MX hosts to send; many inbound-only providers don’t send mail for you. Relying on mx can accidentally authorize large ranges. Prefer explicit ip4/ip6 for known outbound hosts. AutoSPF can show you which mx ranges you would actually grant. ### Can I have multiple SPF records if I split them across multiple TXT strings? - You can have multiple strings in one TXT record, but only one `v=spf1` record per name. Multiple records cause permerror. AutoSPF ensures **single-record publication** even when string-chunking is needed. ### How do I handle bounce domains for third-party ESPs? - Use a dedicated subdomain (e.g., bounce.example.com) as MAIL FROM with its own SPF, and configure the ESP to use it. This preserves DMARC alignment. AutoSPF provisions and maintains per-subdomain SPF automatically. ### Will moving to -all hurt deliverability? - If your sender inventory is complete, `-all` improves trust and reduces spoofing. Stage via `~all` with monitoring; move to `-all` once unknown senders are negligible. AutoSPF provides readiness **scoring and a rollback plan**. ## Conclusion: Make SPF Reliable with Syntax Mastery and Automation Mastering SPF syntax—mechanisms, qualifiers, modifiers, CIDR, macros—and respecting the evaluation and lookup rules is how you fix authentication issues decisively: publish one well-ordered, lookup-budgeted record that ends with the right all qualifier and aligns with DMARC. _AutoSPF operationalizes these best practices by discovering senders, simulating evaluation, preventing multiple-record or over-lookup errors, and safely flattening volatile includes with continuous monitoring_. The result is simple: fewer [SPF errors](https://autospf.com/blog/spf-errors-troubleshooting-guide/), stronger DMARC alignment, and measurably better deliverability—without the daily DNS micromanagement. ![Brad Slavin](https://media.mailhop.org/autospf/images/authors/brad-slavin.jpg) [ Brad Slavin ](/authors/brad-slavin/) General Manager Founder and General Manager of DuoCircle. Product strategy and commercial lead for AutoSPF's 2,000+ customer base. [LinkedIn Profile →](https://www.linkedin.com/in/bradslavin) ## Ready to get started? Try AutoSPF free — no credit card required. [ Book a Demo ](/book-a-demo/) ## Related Articles [ Foundational 17m 10 Reasons The SPF Standard Is Essential For Protecting Your Domain Nov 20, 2025 ](/blog/10-reasons-the-spf-standard-is-essential-for-protecting-your-domain/)[ Foundational 5m 4 ChatGPT and AI-based scams to be wary of in the second half of 2024 Aug 16, 2024 ](/blog/4-ai-and-chatgpt-scams-to-watch-for-in-2024/)[ Foundational 6m 6 Steps to Outplay BEC Attackers Feb 2, 2024 ](/blog/6-steps-to-outplay-bec-attackers/)[ Foundational 4m 7 Myths and Misconceptions about Sender Policy Framework May 31, 2024 ](/blog/7-myths-and-misconceptions-about-sender-policy-framework/) ```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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Resolve SPF lookup limits, flatten SPF records, and maintain email deliverability across all your domains.","publisher":{"@type":"Organization","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. Resolve SPF lookup limits, flatten SPF records, and maintain email deliverability across all your domains.","parentOrganization":{"@type":"Organization","@id":"https://www.wikidata.org/wiki/Q138883901","name":"DuoCircle LLC","url":"https://www.duocircle.com","sameAs":["https://www.wikidata.org/wiki/Q138883901","https://www.crunchbase.com/organization/duocircle-llc","https://www.linkedin.com/company/duocircle","https://github.com/duocircle"],"subOrganization":[{"@type":"Organization","@id":"https://www.wikidata.org/wiki/Q138898167","name":"DMARC Report","url":"https://dmarcreport.com"},{"@type":"Organization","@id":"https://www.wikidata.org/wiki/Q138897474","name":"AutoSPF","url":"https://autospf.com"},{"@type":"Organization","@id":"https://www.wikidata.org/wiki/Q138897912","name":"Phish Protection","url":"https://www.phishprotection.com"}]}}} ``` ```json [{"@context":"https://schema.org","@type":"BlogPosting","headline":"Fix SPF Authentication Issues By Understanding These Syntax Rules","description":"Learn the essential SPF syntax rules to identify and fix authentication errors, improve email deliverability, and protect your domain from spoofing.","url":"https://autospf.com/blog/fix-spf-authentication-issues-by-understanding-these-syntax-rules/","datePublished":"2026-06-16T00:00:00.000Z","dateModified":"2026-06-16T00:00:00.000Z","dateCreated":"2026-06-16T00:00:00.000Z","author":{"@type":"Person","@id":"https://autospf.com/authors/brad-slavin/#person","name":"Brad Slavin","url":"https://autospf.com/authors/brad-slavin/","jobTitle":"General Manager","description":"Brad Slavin is the founder and General Manager of DuoCircle, the company behind AutoSPF, DMARC Report, Phish Protection, and Mailhop. He founded DuoCircle in 2014 to solve the SPF 10-DNS-lookup problem at scale and has led the company's growth to 2,000+ customers. Brad's focus is product strategy, customer relationships, and the commercial and compliance side of email authentication (DPAs, SLAs, enterprise procurement) rather than hands-on DNS engineering.","image":"https://media.mailhop.org/autospf/images/authors/brad-slavin.jpg","knowsAbout":["Email Security Strategy","SaaS Product Management","Enterprise Compliance","Customer Success","Email Deliverability Business"],"worksFor":{"@type":"Organization","name":"AutoSPF","url":"https://autospf.com"},"sameAs":["https://www.linkedin.com/in/bradslavin"]},"publisher":{"@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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[AutoSPF](https://autospf.com/) flags both and offers safer alternatives."}},{"@type":"Question","name":"Does mx automatically authorize my inbound filtering provider to send?","acceptedAnswer":{"@type":"Answer","text":"- mx authorizes the IPs of your MX hosts to send; many inbound-only providers don’t send mail for you. Relying on mx can accidentally authorize large ranges. Prefer explicit ip4/ip6 for known outbound hosts. AutoSPF can show you which mx ranges you would actually grant."}},{"@type":"Question","name":"Can I have multiple SPF records if I split them across multiple TXT strings?","acceptedAnswer":{"@type":"Answer","text":"- You can have multiple strings in one TXT record, but only one `v=spf1` record per name. Multiple records cause permerror. AutoSPF ensures **single-record publication** even when string-chunking is needed."}},{"@type":"Question","name":"How do I handle bounce domains for third-party ESPs?","acceptedAnswer":{"@type":"Answer","text":"- Use a dedicated subdomain (e.g., bounce.example.com) as MAIL FROM with its own SPF, and configure the ESP to use it. This preserves DMARC alignment. AutoSPF provisions and maintains per-subdomain SPF automatically."}},{"@type":"Question","name":"Will moving to -all hurt deliverability?","acceptedAnswer":{"@type":"Answer","text":"- If your sender inventory is complete, `-all` improves trust and reduces spoofing. Stage via `~all` with monitoring; move to `-all` once unknown senders are negligible. 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