How To Fix SPF Permerror And Improve Email
Deliverability


The Sender Policy Framework (SPF) serves as an essential protocol for email authentication, designed to combat email spoofing by outlining which mail servers are authorized to send messages on behalf of your domain. A frequent challenge that can significantly affect your email deliverability is the SPF Permerror (permanent error). This issue arises when the receiving server encounters difficulties processing the SPF record, typically stemming from configuration errors.

In this in-depth guide, we will examine methods to resolve SPF Permerror and offer step-by-step instructions to enhance your SPF record for optimal deliverability. Uncover the wide range of services we offer here.


What is an SPF Permerror?


An SPF Permerror signifies that the receiving server is unable to interpret the SPF record because of significant problems within the DNS configuration. In contrast to "Fail" or "SoftFail" outcomes, a Permerror halts the SPF verification process entirely. This can lead to valid emails being either rejected or incorrectly classified as spam.

Common causes include:

  • Too many DNS lookups (exceeding the 10 DNS lookup limit)

  • Syntax errors in the SPF record

  • Multiple SPF records for the same domain

  • Use of deprecated or invalid mechanisms


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Common Causes and How to Fix Them


Exceeding the 10 DNS Lookup Limit

SPF records allow for a maximum of 10 DNS mechanism lookups. This limit encompasses various mechanisms such as include, a, mx, ptr, and exists.

  • Fix: Reduce the frequency of include statements, as each one incurs a DNS lookup.

  • Flatten your SPF record: Utilize SPF flattening tools to substitute 'includes' with IP addresses, such as:

    • EasyDMARC

    • MXToolbox

    • SPF-Record.com

  • Consolidate services: Use fewer third-party email services if possible.

Multiple SPF Records

A domain is permitted to contain only a single SPF record; the presence of multiple records will lead to a Permerror.

Fix: Combine all SPF entries into a single TXT record.

Example of a correct SPF record:

v=spf1 include:_spf.google.com include:spf.mailer.net -all

Syntax Errors

A minor error, whether it be an unintended space or a faulty mechanism, has the potential to compromise your SPF record.

Fix: Validate your SPF record using:

  • Kitterman SPF Validator

  • MXToolbox SPF Checker

Ensure:

The record begins with v=spf1

There’s only one -all, ~all, or ?all directive at the end

Using Deprecated Mechanisms

Mechanisms like ptr and exist are discouraged and can cause SPF issues.

Fix: Remove or replace deprecated mechanisms.

Use ip4 or ip6 for direct IP authorization.



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Best Practices for Optimizing SPF and Deliverability


  • Use a Reputable Mail Provider: When utilizing services such as Gmail, Office 365, Mailchimp, or any trusted email service provider (ESP), it is imperative to adhere strictly to their specified SPF configuration instructions. Failing to implement the correct include mechanisms for these platforms can result in errors and the potential rejection of messages.

  • Flatten SPF Records Safely: Flattening involves substituting domain names with their corresponding IP addresses, thereby minimizing the need for DNS queries. However, it is essential to perform this process regularly, as IP addresses are subject to change. To facilitate this, consider employing automated tools or scripts that track DNS modifications.

  • Monitor SPF with DMARC Reports: Establish DMARC with rua reporting to gain insights into SPF alignment challenges. The generated reports will provide:

    • Which emails are failing SPF

    • If SPF is aligned

    • If unauthorized IPs are trying to spoof your domain

  • Use Subdomains for Third-Party Senders: When employing various third-party email services, it is advisable to assign them to distinct subdomains, each equipped with its own SPF records. For instance:

    • marketing.example.com → Mailchimp

    • support.example.com → Zendesk

    • This keeps the main domain’s SPF lean and manageable.

Addressing SPF permerrors is essential for ensuring effective email deliverability, safeguarding your domain's reputation, and enhancing security measures. By systematically reviewing your SPF records, adhering to the 10 DNS lookup limit, and implementing validated and optimized entries, you can greatly minimize the likelihood of your emails being categorized as spam or rejected.

It is also advisable to integrate SPF with DKIM and DMARC, forming a robust and multifaceted email authentication system. Ongoing monitoring and meticulous configuration are key to guaranteeing that your emails land in inboxes rather than being diverted to junk folders.