What is Sender Policy Framework (SPF)?

What is SPF? SPF as mentioned under RFC 7208 is an email authentication standard that protects organizations against impersonation. The biggest threat to your customer’s email security is an attacker using your brand name and domain to send fake messages. Phishing emails like these can be convincing enough that your customers won’t know the difference — and end up falling prey to a scam. This can damage both your brand image and your reputation with email providers, making it less likely that your actual emails reach customer inboxes.

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History of Sender Policy Framework (SPF)

To learn about what is SPF, we have to travel back to the early 2000s when it was first introduced. The Sender Policy Framework (SPF) is a method of authentication that enables mail receivers to verify the source domains of email messages. In the early 2000s, there were a few proposals for how email could be authenticated. Among those was “Reverse MX” (RMX) by Hadmut Danisch and “Designated Mailer Protocol” (DMP) by Gordon Fecyk.

However, these two proposals were merged in the year 2003 by the Founder of Pobox and Singapore-based notable entrepreneur, Meng Weng Wong. Over the next couple of years, several alterations were underway with specialists and security engineering soliciting over SPF.

In 2005, SPF was recognized as an Internet Engineering Task Force (IETF) experimental standard. Finally, in 2006, SPF was published with RFC 4408 as the specification (as experimental).

Did you know?

SPF was earlier an acronym for Sender Permitted From ( also called SMTP+SPF). In February of 2004, SPF came to be known by the popular acronym that we are familiar with today, which is: Sender Policy Framework.

The Current State of SPF

Moving on from history, let’s check out what is SPF’s current state. The current version of SPF in use is 2.0 and is defined in RFC 7208 from 2014. It is now supported by all major email providers such as Microsoft (Outlook), Google (Gmail), Yahoo Mail, AOL, Hotmail/Outlook Live, and more.

Originally, SPF was designed to prevent email spoofing and email phishing by allowing email senders to declare which servers they are allowed to send mail from. Since then, the protocol has evolved in many ways and has been implemented in some form by almost all popular email servers.

Yet at the same time, it has remained misunderstood by many companies who use it—and as a result, is often misused or poorly configured. This is where PowerSPF comes in!

What is SPF doing for you? : Block Out Unauthorized Senders

If you’re wondering what is SPF doing for your organization, here us out! Sender Policy Framework, or SPF, is one of the earliest and most widely used industry standards for email security. It operates on a simple concept: only allow explicitly authorized senders to send emails from your domain, and block everyone else. When you implement SPF on your domain, here’s what happens:

Publish SPF Records
You must publish SPF records on your DNS, containing a list of all approved IP addresses that can send emails.
Email Server Authentication
When a receiving email server sees an email from your domain, it crosschecks the sender’s IP address with the list you provided.

If the sender’s IP matches one on the list, it gets authenticated and is sent to the destination inbox. If it doesn’t match, the email fails authentication and gets rejected by the server.

SPF for Third-Party Vendors

What is SPF for your third-party vendors? To align your third parties for SPF, you need to include IP addresses or SPF-handling domains unique to them in your domain’s record. But beware, do not include multiple SPF records for the same domain!

For example, if you are using SuperEmails.net as your email sender, and their SPF-handling domain is spf.superemails.net, your SPF record might be:

v=spf1 include:spf.superemails.net -all

We have got you covered. Our knowledge contains a list of famous third-party email vendors with specific instructions on how to configure the protocol for each of them.

The Limitations of SPF

While SPF does protect your domain against spam and forged sender addresses, it is not all perfect! For example:

SPF + DKIM = DMARC
DMARC uses both SPF and DKIM (DomainKeys Identified Mail) technologies in tandem to give your domain even better protection against spoofing. PowerDMARC takes this one step further with AI-based real-time threat modeling that uncovers spoofing attacks around the globe.
Reporting & Feedback With PowerDMARC
Neither SPF nor DKIM give the domain owner feedback about emails that fail authentication. DMARC sends detailed reports directly to you, which the PowerDMARC app converts into easy-to-read charts and tables. Using the analytics data, you can change your email marketing strategy on the fly.
Control What Happens to Unauthenticated Email
DMARC lets you, the domain owner, decide whether email that fails validation goes to inbox, spam or gets rejected. With PowerDMARC, all you have to do is click one button to set your DMARC policy. It’s that easy.

The last two restrictions can be easily bypassed by using our dynamic SPF flattening tool.

Make SPF Even Better With PowerDMARC

SPF by itself is still effective, but cybercriminals have come up with ways to bypass the IP address verification phase. But SPF technology is made relevant again by incorporating it into DMARC. What are the benefits of doing this? We’ll tell you:

SPF + DKIM = DMARC
DMARC uses both SPF and DKIM (DomainKeys Identified Mail) technologies in tandem to give your domain even better protection against spoofing. PowerDMARC takes this one step further with AI-based real-time threat modeling that uncovers spoofing attacks around the globe.
Reporting & Feedback With PowerDMARC
Neither SPF nor DKIM give the domain owner feedback about emails that fail authentication. DMARC sends detailed reports directly to you, which the PowerDMARC app converts into easy-to-read charts and tables. Using the analytics data, you can change your email marketing strategy on the fly.
Control What Happens to Unauthenticated Email
DMARC lets you, the domain owner, decide whether email that fails validation goes to inbox, spam or gets rejected. With PowerDMARC, all you have to do is click one button to set your DMARC policy. It’s that easy.