What is an SPF Record? Its Role and Impact on Email Security/Deliverability

Emails are a powerful mode of communication and marketing. Modern-day marketers utilize them for personalized marketing outreach, B2B communication, and providing digital services, such as newsletters.

However, all of these benefits require that your email security and deliverability be high. Email deliverability is a metric of trust that email service providers (ESPs) and Internet Service Providers (ISPs) use. This metric assesses the trustworthiness of emails from a specific domain and determines whether they should be delivered to the inbox or rejected.

Fortunately, there are several ways to improve email deliverability with ease. The number one method among them is using a DNS record called SPF, or the Sender Policy Framework. 

Let’s examine what that DNS SPF record is and how it works to enhance email deliverability and security. 

What Is SPF Record?

SPF is a specific type of DNS TXT record. It stands for Sender Policy Framework. The role of SPF is to specify which mail servers are authorized to send emails on behalf of a domain. This authorization is used to prevent email spoofing and let recipients know that the email is from a legitimate source. This also improves email deliverability.

So, if you had a domain called “example.com,” its SPF record would contain the names or IP addresses of all email servers that can send emails from “example.com.”

Here’s what the SPF record looks like.

TXT google.com 3600 v=spf1 include:_spf.google.com ~all

Here’s what the text means

• TXT (Blue): signifies the type of record. Since SPF is a type of TXT record, this field says “TXT.”
• Google.com. (Pink ): specifies which domain the record is for.
• 3600 (Yellow): shows the time to live (TTL) for the record in seconds.
• V=spf1…(Green): shows the value of the TXT record.

The green text is the important part here. Here’s a breakdown of the information it provides.

• “v=spf1” tells us that this is an SPF (Sender Policy Framework) record.
• “Include:” indicates that everything following this section is authorized to send emails on behalf of the domain.
• “_spf.google.com” is a nested SPF record. It tells the server to also check the SPF record found at “_spf.google.com” and trust the IP addresses listed there. So, any IPs listed in that record are automatically authorized for google.com as well.
• “~all” means that all other IP addresses other than the ones in the include command are not authorized to send emails on behalf of Google.com.

You can look up an SPF record with online tools or a command prompt/terminal command.

How Does SPF Enhance Email Security?

SPF and email security are closely related. To understand, let’s take a look at Spoofing.

Spoofing is a security hazard where anyone on the internet can profess themself to be someone else. This is usually done to hijack the perceived trust of a different entity and use it for a scam or fraud.

Email spoofing is one of the most common methods of doing this because it is relatively easy to spoof a domain name and claim that the email is from it. 

As you can imagine, people have used email spoofing to impersonate Facebook support or Microsoft support and defraud others out of a significant amount of money.

You can read about famous hacks that used email spoofing right here.

SPF was designed to prevent email spoofing and enhance email security. Here’s a breakdown. 

It is easy to spoof a domain name. It's tough to spoof an IP address. This is due to the extensive knowledge required to spoof IP addresses and the advanced security measures that can easily detect spoofed IP addresses.

Since SPF records dictate which IPs are authorized, any spoofed email that is not from those IPs is immediately rejected and never lands in the inbox. 

As a result, customers don’t face fraudulent emails from your domain. SPF records are easy to create, so most domains have them in place. Therefore, scammers often struggle to scam someone via email.

How Does SPF Enhance Email Deliverability?

ESPs and ISPs keep note of several factors that they use to calculate whether to deliver an email or reject it. Many of these factors are affected by the presence of an SPF record.

The following are some notable factors related to the SPF record.

• Sender Reputation: This metric determines whether emails from a domain are sent in good faith or not (i.e., whether they are spam). A history of good sending behavior ensures higher deliverability. SPF records help maintain the sender's reputation by ensuring that nobody can spoof the domain and send spam. As a result, all emails from the domain are sent in good faith, which boosts the sender's reputation.
• Authentication Records: SPF, DKIM, and DMARC help verify the sender’s identity. Just having this authentication gives your domain credibility. As a result, ISPs/ESPs are more likely to deliver your emails to inboxes.
• Spam Complaints: Frequent complaints can cause emails to be flagged as spam. These occur when your domain is spoofed, and people receive spam that is perceived to be from your domain. Since SPF records dictate which email servers are legitimate, ISPs/ESPs reject all emails that aren’t from them. This means that spam emails sent from spoofed email addresses are rejected, resulting in fewer complaints, which in turn boosts your sender reputation and deliverability.
• Blacklists: Being listed on blacklists can block email delivery. A domain typically ends up in a blacklist if there are many spam complaints against it. 

As we already discussed, SPF records prevent spoofing which results in fewer spam complaints, so your domain does not get blacklisted. This means your deliverability is not affected.

SPF records authenticate your domain by listing the IP addresses that are authorized to send emails on its behalf. This ensures that your domain is not spoofed; as a result, you won’t receive any complaints about your domain, and it also won't end up on any blacklists. Naturally, this boosts your sender reputation and, as a result, enhances your email deliverability.

How to Verify Your SPF Records?

Due to the value provided by SPF records, you need to be prudent in their maintenance. 

Whenever you add or remove any email servers from use, you need to update the SPF records to reflect those changes. Otherwise, your domain reputation and email deliverability can suffer.

Updates can often result in errors due to small errors in the record’s value. This is why verifying your SPF records is necessary. Here’s how you can do it.

• Go online and open a browser.
• Open an Online SPF Lookup tool 
• In the tool, enter the name of your domain and select the DNS servers whose records you want to check.
• Click on “SPF Lookup” and wait for your results
• The results will display numerous details about the SPF records, including their values and the number of lookups they have. 

In this way, you can validate and verify your SPF records.

Conclusion

This was the inside scoop on SPF records and how they enhance email security and deliverability. SPF records are just one of the DNS records that can enhance email deliverability; the other two are DKIM and DMARC. We will discuss those two topics in separate articles at a later time. By now, you should have understood the basics of SPF records, their role in emails, and their importance. Therefore, ensure that you validate them to protect your domain.