SPF Record Lookup Limits

### Explanation of the SPF Lookup Limit
When an email is received, the receiving server will check the sending domain's SPF record to verify if the email is coming from an authorized server. During this process, the server performs DNS lookups for mechanisms like:

– `include`
– `a`
– `mx`
– `ptr` (deprecated)
– `exists`
– `redirect`

If the total number of DNS lookups exceeds **10**, the SPF check will fail with a `permerror` (permanent error), potentially causing your emails to be rejected or marked as spam. This could lead to **reduced email deliverability**.

### Common Causes of Excessive DNS Lookups
The most common cause of exceeding the limit is using too many `include` statements or having nested includes, where each included domain can trigger additional DNS lookups.

For example:

v=spf1 include:_spf.google.com include:_spf.mailgun.org include:sendgrid.net ~all

If each of these `include` directives further references other domains, the number of DNS lookups can quickly exceed the limit.

### Strategies to Optimize Your SPF Record
1. **Remove Unused Includes**: Audit your SPF record and remove any `include` statements that are not in use.

2. **Flatten SPF Records**: This means replacing `include` statements with the actual IP addresses or ranges they resolve to. There are online tools that can help flatten SPF records, but be cautious as IPs might change over time.

3. **Use Subdomains**: If your domain has too many sending services, consider using subdomains with separate SPF records for different purposes (e.g., `sales.yourdomain.com`, `marketing.yourdomain.com`).

4. **Leverage SPF Macros**: Although less common, SPF macros can sometimes reduce lookups if implemented properly.

5. **Use DNS SPF Record Optimization Tools**: Tools like **Valimail**, **MXToolbox**, or **DMARCLY** can help you analyze and optimize your SPF records to ensure you're within the lookup limit.

### Example of an Optimized SPF Record
Before:

v=spf1 include:_spf.google.com include:_spf.mailgun.org include:sendgrid.net include:_spf.salesforce.com ~all

After flattening:

v=spf1 ip4:192.168.1.1 ip4:203.0.113.0/24 ip4:198.51.100.0/25 ~all

By optimizing your SPF records to stay within the 10 DNS lookup limit, you can improve your email deliverability and ensure compliance with SPF checks.

### Step 1: Access Your Domain's DNS Management Console
1. **Log in to your Domain Registrar or DNS Provider**:
– This could be GoDaddy, Cloudflare, Namecheap, AWS Route 53, Google Domains, or any other service where your domain is managed.
2. **Navigate to the DNS Management Section**:
– Look for options like **DNS Settings**, **DNS Management**, **Zone Editor**, or **DNS Records**.

### Step 2: Locate Your Existing SPF Record
1. **Look for a TXT Record with SPF Data**:
– Your SPF record will typically be a **TXT record** with content starting with `v=spf1`.
– Example:

v=spf1 include:_spf.google.com include:_spf.mailgun.org ~all

### Step 3: Analyze Your SPF Record for DNS Lookups
You can use online tools to check how many DNS lookups your current SPF record is performing:
– **Valimail Lookup Tool**: [Valimail SPF Checker](https://tools.valimail.com/spf-checker)
– **MXToolbox SPF Check**: [MXToolbox SPF](https://mxtoolbox.com/spf.aspx)
– **DMARCLY SPF Surveyor**: [DMARCLY SPF Lookup](https://www.dmarcly.com/tools/spf-surveyor)

These tools will show you the total number of DNS lookups and help identify which includes are contributing to the count.

### Step 4: Optimize Your SPF Record
1. **Remove Unnecessary Includes**:
– If there are any services you no longer use, remove their `include` statements.

2. **Flatten Your SPF Record**:
– You can manually resolve `include` statements to their IP addresses using command-line tools (like `nslookup` or `dig`) or online services.
– Alternatively, use an **SPF flattening tool** to generate a new SPF record with reduced lookups:
– [SPF Record Flattening Tool](https://tools.valimail.com/spf-flattener)

3. **Update Your SPF Record**:
– Edit the existing TXT record with the optimized SPF value.
– Save the changes in your DNS management console.

### Step 5: Verify Your New SPF Record
1. **Use SPF Validation Tools**:
– After updating your SPF record, verify it using the tools mentioned above to ensure it does not exceed the 10 DNS lookup limit.

2. **Test Email Deliverability**:
– Send test emails to check if your emails are passing SPF checks. Services like **Mail-Tester** ([mail-tester.com](https://www.mail-tester.com/)) or **MXToolbox Email Deliverability** can help.

### Example of How to Modify the SPF Record (on Cloudflare)
1. Go to the **DNS** tab for your domain.
2. Find the existing **TXT** record with `v=spf1`.
3. Click the **Edit** button next to the record.
4. Update the SPF value (e.g., removing or flattening includes).
5. Click **Save** to apply the changes.

### Notes
– **Propagation Time**: DNS changes may take up to 48 hours to propagate fully, though they often update much sooner.
– **Testing**: Always test your changes thoroughly to ensure your email deliverability isn't negatively affected.

By following these steps, you can optimize your SPF record to stay within the 10 DNS lookup limit, thus improving your email deliverability and reducing the risk of emails being flagged as spam.

### Step 1: Review Your SPF Record
1. **Access Your SPF Record**:
– Log in to your domain's DNS management console and locate the existing SPF record.
– Copy the contents of your SPF record, which looks something like this:

v=spf1 include:_spf.google.com include:spf.protection.outlook.com include:_spf.mailgun.org ~all

2. **List All Services**:
– Break down your SPF record to list all the services/domains included (e.g., Google, Microsoft, Mailgun).

### Step 2: Analyze Your Email Sending Services
1. **Audit Your Email Configuration**:
– Make a list of all email services and platforms your organization uses, such as Google Workspace, Microsoft 365, Mailgun, SendGrid, or any custom SMTP servers.

2. **Check Email Headers for Active Services**:
– Send a test email from your domain to a third-party email account (e.g., Gmail).
– View the full email headers by opening the email and selecting "Show Original" or "View Headers" (depending on the email client).
– Look for `Received-SPF`, `Received`, or `Authentication-Results` headers to identify which services are actively sending emails on your behalf.

Example:

Received-SPF: pass (google.com: domain of sender@example.com designates 192.0.2.1 as permitted sender)
   Authentication-Results: spf=pass (sender IP is 192.0.2.1) smtp.mailfrom=example.com

3. **Analyze Email Logs**:
– If you have access to your email server logs (like through cPanel, Postfix, or another email server), review them to see which IP addresses or services have been sending emails.

### Step 3: Use DNS and SPF Analysis Tools
1. **Valimail, MXToolbox, or DMARCLY**:
– Use these tools to analyze your SPF record for all `include` statements and related DNS lookups.
– [Valimail SPF Checker](https://tools.valimail.com/spf-checker)
– [MXToolbox SPF Check](https://mxtoolbox.com/spf.aspx)
– [DMARCLY SPF Lookup](https://www.dmarcly.com/tools/spf-surveyor)

2. **Check for Obsolete Includes**:
– Look up each included domain (e.g., `_spf.mailgun.org`) using tools like `nslookup` or `dig`:

nslookup -type=txt _spf.mailgun.org
     dig txt _spf.mailgun.org

– Ensure these services are still active and necessary for your current email setup.

### Step 4: Verify with Your Teams or Service Providers
1. **Confirm with IT and Marketing Teams**:
– Check with your internal teams to confirm if they are still using services like Mailgun, SendGrid, or any other email marketing platforms.

2. **Log in to Service Dashboards**:
– Log in to the admin panels of the services listed in your SPF record to see if they are still actively used.
– For example, check your Mailgun or SendGrid dashboard for recent activity.

### Step 5: Temporarily Comment Out Suspected Unused Services
1. **Test by Removing/Commenting Unused Includes**:
– Temporarily remove or comment out suspected unused `include` statements in your SPF record.
– Example (before):

v=spf1 include:_spf.google.com include:_spf.mailgun.org ~all

– Example (after):

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

2. **Monitor Email Deliverability**:
– After making changes, monitor email deliverability for a few days using services like:
– [Mail-Tester](https://www.mail-tester.com/)
– [GlockApps](https://glockapps.com/)
– [MxToolbox Email Deliverability](https://mxtoolbox.com/deliverability)
– If you notice issues with specific emails not being delivered, re-add the removed includes.

### Summary
By following these steps, you can identify unused email services, remove unnecessary `include` statements, and optimize your SPF record to stay within the 10 DNS lookup limit. This will help improve email deliverability and reduce the risk of your emails being marked as spam.