How To Perform An SPF Lookup And
Fix Common Issues


Conducting an SPF lookup is essential for maintaining email security, as it ensures that only approved servers can dispatch emails from your domain, thereby reducing the risk of spam and phishing threats. This guide provides a step-by-step approach to performing an SPF lookup and addressing typical problems that may occur.


What is SPF and Why is it Important?


When an email is dispatched from your domain, the recipient's mail server consults the SPF record to confirm that the sending server is among those authorized. The email may be classified as spam or outright rejected if the check fails.

Having an accurate SPF record is crucial for multiple reasons:

  • Minimizes Phishing Risks: A precise SPF record helps block unauthorized servers from dispatching harmful emails that appear to originate from your domain.

  • Enhances Email Delivery Rates: Messages sent from recognized servers have a lower chance of being flagged as spam.

  • Safeguards Your Domain’s Reputation: Keeping an up-to-date SPF record protects your domain from potential blacklisting.


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How to Perform an SPF Lookup


To conduct an SPF lookup, you need to verify the SPF record associated with your domain to confirm that it is set up correctly. Here’s the process to follow:


1. Use an SPF Lookup Tool

Popular options include MXToolbox, DNSstuff, and Kitterman’s SPF checker. To utilize one of these tools, follow these steps:

  • Go to any of the aforementioned SPF lookup websites.

  • Input your domain name into the search field and select "Check SPF Record."

  •  The tool will retrieve and present the SPF record linked to your domain for your review.

  •  If your domain lacks an SPF record, the tool will display a notification stating that no SPF record is found for your domain.

2. Manually Check the DNS Record

This can be accomplished by utilizing the nslookup or dig commands in your terminal or command prompt. For instance, if you want to check an SPF record using nslookup, you would type:

nslookup -type=txt yourdomain.com


Common SPF Issues and How to Fix Them


1. No SPF Record Found

If your domain's SPF lookup indicates there is no SPF record present, you'll have to establish one by incorporating a TXT record into your domain's DNS configuration. To do this, access the DNS management section of your domain registrar’s website and create a new TXT record formatted like this: "v=spf1 include:_spf.google.com ~all."Be sure to adjust it according to your email service provider's specifications. After saving your modifications, be patient as the DNS updates may take from several minutes to as long as 48 hours to fully take effect.


2. SPF Record is Too Long

SPF records are restricted to a maximum size of 512 bytes. If your SPF record surpasses this threshold, it may get cut off, resulting in an unsuccessful lookup. To resolve this issue, consider using the "include" mechanism to point to other domains that are permitted to send emails for you.



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3. Too Many DNS Lookups

SPF records have the ability to point to other domains; however, you are restricted to a maximum of 10 DNS lookups. Surpassing this threshold will fail the SPF verification.

To resolve this issue:

  • Examine your SPF record to check if it points to an excessive number of external domains.

  • Combine SPF records from various domains or eliminate any redundant references to lower the lookup count.

  • Utilize the "include" mechanism solely for reputable providers and steer clear of over-nesting.

4. Softfail (~all) vs. Hardfail (-all)

SPF records utilize the "all" mechanism to indicate the handling of emails sent from unauthorized servers. In your record, you might come across either ~all (softfail) or -all (hardfail).

To resolve this issue:

A softfail (~all) permits the email to go through but flags it as potentially problematic, whereas a hardfail (-all) outright denies the email. If you are confident in your SPF configuration and wish to implement stricter measures, consider changing ~all to -all in your SPF record. Exercise caution, though, as an incorrect record may result in the rejection of some legitimate emails. Get additional details here.


5. SPF Record Is Not Updating

If you've made recent updates to your SPF record and aren't seeing the changes take effect, it could be a result of DNS caching problems.

Here's how to resolve it:

  • Either clear your local DNS cache or allow time for DNS propagation to finish.

  • Use an alternative SPF lookup tool to verify that the record has been updated correctly.