SPF Record Tester: Why SPF Admins Need to Use it?

An SPF record tester, also known as an SPF validator, is one of the free diagnostic tools designed to examine and validate a domain’s SPF DNS record to verify email senders’ authenticity whilst enhancing email delivery and security by preventing spamming and phishing. It looks for inconsistencies in the syntax, name servers, and IP addresses of TXT records published on the DNS of your company’s domain.

How Does an SPF Record Checker Help?

A credible tool performs an SPF record check against the following:

• Presence of an SPF record
• Existence of multiple SPF records
• SPF syntax errors
• Maximum lookup limit
• Use of a PTR mechanism
• Use of the +all Qualifier
• Characters after the ‘all’ Qualifier
• SPF type DNS
• Maximum void lookups
• MX resource records
• Null values

If any of these are highlighted as errors upon an SPF check, your SPF record may fail to perform properly, and your email messages may fail to reach the primary inbox of your desired recipient. This would result in a communication gap, which isn’t appreciated.

Best Practices to Maintain an Error-Free SPF Record

Incorrect SPF DNS records can inadvertently lead to legitimate emails being marked as spam or rejected outrightly, causing communication disruptions and potential business losses. That’s why it is crucial to maintain a robust and error-free SPF record in order to safeguard your domain’s reputation and improve the chances of your legitimate email messages reaching recipients’ inboxes.

Here’s how you can maintain an error-free SPF record and ensure a high email deliverability rate. 

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Keep a Tab on Your Return-Path Domain

When configuring your SPF record, it’s crucial to limit the sources that have your Return-Path domain. This means that third-party email service providers (ESPs), such as Mailchimp, which handle your bounces on their domain, should not be part of your SPF record as they use their own domain in the Return-Path address. Moreover, for such sources, using the include tag in your SPF record isn’t necessary. 

Stick to “~all” or “-all” Mechanisms

When it comes to optimizing SPF records, the recommended way to go about it is by using -all (Fail) and ~all (SoftFail) mechanisms instead of +all” (Pass) or “?all” (Neutral) policies. Both “-all” and “~all” contribute to improved email security by preventing email spoofing and phishing attacks, ensuring a safer and more reliable email communication experience for both senders and recipients.

Avoid Using the redirect Modifier

It may seem convenient to redirect to another domain’s SPF record, however, such steps are examples of how limitations can get imposed on your email strategy and validity. Using “redirect=” restricts the flexibility of adding other sources to your SPF record, hindering your organization’s ability to use multiple email strategies effectively. Instead, you can opt for a more comprehensive approach by directly including all authorized mail servers in your SPF record using the include Mechanism. 

Complement SPF Record with DKIM and DMARC 

While SPF is an integral tool to prevent phishing and spoofing, it is no silver bullet to shield your mail server range and domains. However, by complementing SPF with DKIM (DomainKeys Identified Mail) and DMARC (Domain-based Message Authentication, Reporting, and Conformance), you can create a more robust email authentication framework that results in better protection against spam activities attempted in your name.  

Staying Within the Lookup Limit

There’s a limit of a maximum of 10 DNS lookups, and non-compliance with that causes a Permerror issue. AutoSPF’s SPF flattening service compresses your TXT record, which eliminates the need for unnecessary DNS lookups.

How to Resolve Errors Highlighted upon SPF Lookups?

Despite you being strategic and deliberate about your source SPF TXT record and information loaded in it, an SPF lookup tool can encounter certain issues which can impede everything related to email deliverability. 

Let’s look at how to address these errors effectively to bolster your domain’s email security and reliability.

Verify SPF Records

To avoid potential SPF lookup errors, it’s important to run tests and monitor the accuracy of your SPF record configuration. This means, as domain owners, you should ensure that your SPF record is properly configured and contains all authorized IP addresses (belonging to the ip4 or ip6 range) and mail servers that are allowed to use your company’s domain name for sending emails.

Review IP Addresses

If a certain IP address’s authentication failure is causing a roadblock, make sure that the address is authorized to SPF record is properly configured on behalf of the domain by cross-checking the SPF record or adding it to the allow-list if needed.

Check Email Headers

To fix SPF checker problems, observe the email headers for the “Received-SPF” section. If the header parameter shows “pass,” it means that the IP address is authenticated to send emails on the site or domain’s behalf.

Examine the Alignment

If you encounter an SPF alignment problem, it is essential to test the ESP portal. You should thoroughly review the ESP portal to ensure that you are using the correct domain for the sender’s email address. This will fix any discrepancies and improve the security and deliverability of your emails.