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====== SPF — Sender Policy Framework ======

SPF (Sender Policy Framework) is an email authentication method that prevents spammers from sending emails using your domain.

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===== What is SPF? =====

SPF allows domain owners to specify which mail servers are authorized to send emails on their behalf.

When a receiving mail server gets an email, it checks:

1. The envelope sender domain (Return-Path)
  2. The IP address of the sending server
  3. The SPF record published by the domain owner
  4. If the IP is authorized, SPF passes; otherwise, it fails

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===== SPF Record Format =====

An SPF record is a TXT record published in the domain's DNS:

| example.com. TXT "v=spf1 include:_spf.google.com ~all"

**Components:**

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===== SPF Mechanisms =====

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===== SPF Qualifiers =====

^ Qualifier ^ Meaning ^
| **+** | Pass — authorized (default) |
| **-** | Fail — hard fail (reject) |
| **~** | Soft Fail — mark as spam |
| **?** | Neutral — no policy |

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===== Common SPF Examples =====

**Google Workspace (Gmail):**

| v=spf1 include:_spf.google.com ~all

**Microsoft 365:**

| v=spf1 include:spf.protection.outlook.com ~all

**Custom (self-hosted):**

| v=spf1 a mx ip4:192.168.1.0/24 ~all

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===== SPF Lookup Limits =====

SPF has a hard limit of **10 DNS lookups**. If you exceed this, receivers may reject your email.

**Lookup mechanisms:**
  * include
  * a
  * mx
  * ptr
  * exists
  * redirect

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===== SPF Policy Levels =====

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===== Test Your SPF =====

Use our [[https://telenegar.ir/mailcheck/|Mail Check tool]] to verify your SPF, DKIM, and DMARC records.

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