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Why SPF Matters: Protect Your Business Against Email Spoofing Attacks

Sender Policy Framework (SPF) is an email authentication mechanism that protects businesses against spoofing attacks and unauthorised senders. As a business owner, it's essential to know how it works and understand the benefits of implementing it.

How Does SPF Work?

SPF enables the receiving email server to check that an email claiming to come from a specific domain comes from an IP address authorised by that domain's administrator. An SPF record is published in the DNS as a TXT resource type, specifying allowed-sender hosts for the selected fields.

When an email arrives at its destination, the receiving server looks up the corresponding record and checks if the source IP address of that message matches any of those listed in the SPF record. If not, this is suspicious, as the domain's administrator did not authorise this source.

What are the Benefits?

There are many benefits to your email marketing. Firstly, it prevents spoofing attacks that can be used to steal data or commit fraud, which could be disastrous for your business's reputation and success.

Secondly, it ensures only legitimate senders can use your domain name when sending emails on behalf of your company.

Thirdly, it helps ensure all emails contain accurate information about their origin so that spam filters do not block legitimate emails from your company's address.

This means more customers are likely to receive important messages related to sales or customer service inquiries instead of getting blocked or marked as spam.

Ultimately, you are protecting yourself and your customers by verifying and authenticating where emails are coming from and ensuring that only authorised users can send emails on behalf of your business. This process increases customer trust, improves security, and appears in full headers to show you have taken precautions to protect data.

Risks of an incorrect setup

Recently a security architect named Chris Plummer was able to take advantage of an SPF vulnerability that occurs when it is not implemented or is done so incorrectly.

Using the vulnerability he was able to bypass Google’s authentication checks with spoof email claiming to be sent from UPS, even managing to get it to display the logo and blue check.

BIMI did release a statement that explained the check works as expected and the problem is purely the result of a vulnerability that predates the existence of BIMI and DMARC.

How To Create An SPF Record

In order to create an SPF record you need to specify the version of SPF that you are using, the list of IP addresses that have permission to send email on behalf of the domain, any third party domains that also have permission and lastly, add the ‘all’ tag defining the policy applied if an unauthorised server sends on your behalf.

An example, with a ‘fail’ policy will look a little bit like:
v=spf1 ip4:xxx.xxx.xxx.xxx include: domain.com -all

Once prepared it is possible to use a record checker tool that will compare it with a set of criteria confirming whether it has been set up correctly.

SPF Checker Criteria

To ensure a secure and protected email system, a record checker tool provides stringent security in identifying spoofed emails. These checks involve the criteria of making sure there are fallback mechanisms and that the SPF macro is valid.

Another important factor the checker tool will test for is the number of DNS lookups, it’s important that it does not exceed the maximum of ten; if so, you may need to re-evaluate and simplify the configuration.

Once you have gone through this process and passed the criteria set forth by the checker tool, you can add the record to your DNS as a TXT resource type.

With all criteria met you can have confidence in your email reputation, knowing that only authorised senders will be able to deliver mail on behalf of your domain.

Overall, this distinction between authenticated and non-authenticated emails provides an extra layer of trust for online users relying on messages and communication via emails.


Implementing a Sender Policy Framework correctly is essential for protecting your business, stakeholders and customers.

While creating the TXT records and using the checker tools to verify a correct setup are relatively straightforward, troubleshooting isn’t always so easy.

If you want to avoid all the trouble of setting up an SPF record, having a professional inbox-focused company supporting your email marketing campaigns helps you make the process easier and more efficient.

This way, you'll be able to ensure your business is adequately protected against malicious threats and provide a secure online environment for customers to communicate with you effectively - without having to lift a finger!

At InboxWizards, we offer clients a comprehensive suite of email services to help keep their businesses safe and secure. Contact us today for more information!