How SPF Record Generator Works

SPF (Sender Policy Framework) is published as a DNS TXT record that starts with v=spf1 and then lists mechanisms that define which servers are allowed to send email for the domain. This tool turns your inputs—mail providers, IP addresses, and include domains—into a single SPF policy string you can paste into your DNS manager.

SPF qualifiers control how each mechanism is interpreted. Most mechanisms default to a “pass” qualifier, while the final all mechanism sets the default outcome for everything else. In practice, you typically keep the record simple: list the services that can send mail, then close with one clear policy such as ~all during rollout and -all for strict enforcement.

Because SPF is evaluated by receivers at delivery time, it is important to keep the record maintainable. Each additional mechanism adds complexity, and mechanisms that require DNS queries contribute to the evaluation limit. The generator is designed to encourage “clean SPF”: fewer includes, explicit IPs where possible, and a predictable final policy.

Step-by-Step

• 1. Choose the domain and host: Enter the domain you are protecting and the DNS host label where the SPF TXT record will live (usually @ for the root).
• 2. Add common send sources: Enable A and/or MX mechanisms if your website server or mail exchanger hosts send outbound mail directly.
• 3. Add IP allowlists: Paste IPv4 and IPv6 addresses (optionally with CIDR prefixes) for systems that send mail, such as on‑prem servers, apps, or marketing platforms.
• 4. Add provider includes: Include domains published by providers (for example, Google Workspace or Microsoft 365) using include: so their authorized infrastructure is covered.
• 5. Pick an enforcement policy: Choose how receivers should treat non‑matching senders, typically ~all (soft fail) while testing, then -all (hard fail) once confident.
• 6. Select an output format: Copy the value only, a DNS “row” snippet, or a zone‑file style TXT record that is already split into quoted chunks for providers that enforce 255‑character string limits.

Key Features

Safe SPF mechanism builder

Build SPF strings using the most common mechanisms—a, mx, ip4, ip6, and include—without worrying about ordering or missing the required version tag. The generator outputs a clean, space‑separated policy that follows typical operational conventions.

DNS lookup awareness

SPF evaluation is limited to 10 DNS lookups across mechanisms that trigger queries (such as a, mx, include, exists, and redirect). The tool provides an estimated lookup count for the mechanisms you add, and reminds you that nested includes can increase lookups further.

Length and splitting guidance

Some DNS interfaces store long TXT values as multiple 255‑character quoted strings. This tool can output a zone‑file style TXT record split into chunks so you can paste it into systems that require explicit splitting, while still preserving the exact SPF content.

Input validation and warnings

IPv4/IPv6 entries are checked for basic correctness and optional CIDR prefixes. Invalid entries are surfaced as warnings so you can fix them before publishing. You will also see warnings when you are likely to exceed practical limits, such as very long policies or high lookup counts.

Provider-friendly output formats

Different DNS providers accept TXT records in slightly different ways. Some let you paste a long string and silently split it; others require you to enter multiple quoted strings. The zone‑file output mode formats the record as a single TXT line with properly quoted chunks so you can paste it into advanced DNS editors without reformatting by hand.

Record auditing mindset

SPF records tend to grow over time as teams add new senders. A good audit removes senders that are no longer in use, replaces stacked includes with explicit IPs where feasible, and avoids risky mechanisms. The warnings and metadata in this generator help you spot records that are likely to cause “permerror” due to lookup limits or unreadably long policies.

Practical defaults for quick starts

The form is prefilled with a realistic example so you can generate a valid SPF record immediately. Replace the example values with your real sending sources, regenerate, and publish.

Use Cases

• Google Workspace: Generate an SPF record that includes Google’s published SPF include domain and optionally adds your own outbound relay IPs.
• Microsoft 365: Combine Microsoft’s SPF include value with additional systems like ticketing tools, CRM platforms, or a legacy SMTP relay.
• Marketing platforms: Add dedicated sending IPs or provider includes for email marketing services, while keeping your core domain policy readable.
• Hybrid environments: Maintain authorization for cloud mail plus on‑prem servers, scanners, and application alerts by combining include with ip4/ip6 mechanisms.
• DNS provider constraints: Output a chunked TXT format for DNS consoles that enforce 255‑character string segments or have strict paste behavior.
• Transactional email services: Add allowlisted IPs for providers that send password resets, invoices, and app notifications so transactional mail continues to pass SPF.
• Subdomain separation: Generate a stricter policy for a dedicated sending subdomain (for example, mail.example.com) while keeping the root domain policy minimal.
• Security hardening: Move from a permissive policy to a strict -all policy once you confirm all legitimate senders are covered.

Whether you run a single mailbox provider or an ecosystem of SaaS senders, this generator helps you consolidate authorization into one SPF TXT record and reduces the trial‑and‑error usually involved in publishing a correct policy.

Optimization Tips

Stay under 10 DNS lookups

Every include adds at least one lookup, and includes can themselves contain other includes. Prefer consolidating providers where possible, remove unused platforms, and avoid legacy mechanisms like ptr. If you hit the lookup limit, receivers may treat the result as a permanent error, which can hurt deliverability.

Use soft fail while testing

If you are publishing SPF for the first time or migrating providers, start with ~all so you can monitor results without immediately rejecting mail from unexpected sources. After you confirm all valid senders are included, switch to -all for stronger enforcement.

Prefer explicit IPs over complex indirection

When possible, allowlist stable outbound IP addresses with ip4 and ip6 rather than stacking multiple includes. This keeps the record shorter, reduces lookup usage, and makes troubleshooting easier when mail flow changes.

Keep “all” last and avoid duplicates

Receivers evaluate mechanisms left to right and stop at the first match. Put the all mechanism at the end and avoid repeating the same include or IP entry. A tidy record is easier to audit and less likely to hit provider limits.

FAQ