Every 39 seconds, a cyberattack occurs across the globe, most of which may be perpetrated through email. SPF helps authorize your senders so that your domain cannot be manhandled by an unauthorized third party email sender. To set up SPF is the DNS, you must first know what is SPF record in DNS.

SPF or Sender Policy Framework is an email authentication protocol that allows only specific IPs to send emails using a domain name. Any IP address outside the list will not reach the receiver’s mailbox as it leads to SPF failure.

It protects your email domains from hackers to steer clear of phishing, spamming, and email spoofing attacks. Email authentication techniques like SPF are ideal for keeping your email domain protected. Its structure has 3 main components; mechanism, modifiers, and qualifiers.

This blog will discuss what is SPF record in DNS and more.

What is an SPF record in DNS?

SPF is short for Sender Policy Framework, a DNS TXT record with a list of servers allowed to send emails from a certain domain. It works when domain owners update arbitrary texts into DNS or Domain Name System to track and regulate respective domain names.

To understand the DNS SPF record, let’s quickly see what DNS is.

It’s a system that translates a computer’s host name into an IP address on the internet. All the internet-enabled devices have their IP addresses, which help other devices to locate them.

Now, let’s come back to the main question, ‘what’s an SPF record?.’ Say, if your business uses various sending IPs, you can use PowerDMARC’s free SPF record generator to create an inventory of authorized IPs in the form of a TXT document called SPF record to authenticate genuine IPs allowed to use your domain name.

How do SPF Records Work?

So far, we’ve discussed what is SPF record in DNS, now it’s time to understand how it works. The authentication process starts after you generate an SPF record for your domain. The return path email address is cross-checked at the receiver’s end. A return-path email address is set in the email header, which defines how to handle bounced emails. It verifies whether or not the sending email address is lodged in the SPF records.

If the approval is positive, emails are sent to ‘inbox’; otherwise, it may lead to SPF failure.

SPF Record Structure and Components

DNS SPF record makes your domain credible, trustworthy, and , consequently upholds your company’s image. There’s a proper SPF record structure that helps in maintaining it easily. SPF records have a TXT record type, which is a single string of text.

A DNS SPF record starts with the ‘v=’ element, indicating the version used. ‘SPF1’ is the most common version understood by mail exchanges. The following terms determine mechanisms for verifying whether or not a domain can send emails.

Mechanisms

Here are the eight mechanisms

ALL: It always matches. This shows default results like ‘-all’ for unmatching IPs.
A: Domain name with A or AAAA address record matches as they can be resolved to the sender’s address.
IP4: The match is successful when the sender is linked to the given IPv4 address range.
IP6: The match is successful if the sender belongs to the given IPv6 address range.
MX: Sender’s email address is authorized when their domain name consists of an MX record for resolution.
PTR: The match is validated when the PTR record is linked to a given domain resolving to the client’s address. It’s not suggested as it may block all emails sent using your domain.
EXISTS: It works if the given domain name is validated. This SPF mechanism functions with all resolved addresses.
INCLUDE: It references other domain policies. So, if that passes, it passes automatically. However, if the included policy fails, processing continues.

Modifiers

Modifiers decide the DNS SPF record’s working parameters. It consists of name or value pairs separated by the ‘=’ symbol, pointing out additional information. They’re witnessed several times at the end of the SPF record, and all the unrecognized modifiers are ignored in the process.

The ‘redirect’ modifier directs to other SPF records responsible for efficient functioning. Experts use them whenever more than one domain is linked to the same SPF record. This modifier has to be used if a single entity controls all the domains, otherwise ‘include’ modifier is used.

Qualifiers

Each mechanism can be combined with one of four qualifiers.

‘+’ for PASS result

‘?’ for a NEUTRAL result interpreted like NONE policy.

‘~’ for SOFTFAIL. Usually, messages that return a SOFTFAIL are accepted but tagged.

‘-’ for FAIL, the email is rejected.

Why are SPF Records Used?

The following are the primary reasons for knowing what is SPF record in DNS and its usage.

Averting Cyberattacks

Malicious actors send unauthenticated and fraudulent emails using your domain name to gain the trust of your clients, prospects, stakeholders, etc. They create business email addresses using your domain for attempting phishing, spamming, email spoofing, and other cyberattacks.

However, if you understand the configuration process for the protocol and create one for your company, it’ll be relatively challenging and time-consuming for threat actors to exploit your domain. This will eventually reduce the probability of coming under their radar.

Improving Email Deliverability

Domains without DNS SPF records have high chances of their emails being bounced back or labeled as ‘spam.’ If this persists, the ability to reach the mailbox will be hurt. This means that most emails sent using your domain name will fail to reach the receiver’s end, impacting your business.

DMARC Compliance

DMARC stands for Domain-based Message Authentication, Reporting, and Conformance. It’s another email authentication technique that prevents spamming, phishing, and email spoofing.

It ensures that only permitted entities can send emails through a specific domain. It’s based on SPF and DKIM (another email authentication policy) verification and directs a receiver’s mailbox on how to treat each email received from your domain. Based on this, they’re marked as ‘spam,’ ‘rejected,’ or ‘delivered as normal.’

Moreover, domain administrators can check reports registering their email activity and alter their DMARC policy accordingly. PowerDMARC can make it hassle-free for your business to adopt the DMARC policy by regularly monitoring and adjusting it as per the requirement.

Final Thoughts

SPF-protected email domains repel bad actors as it takes extra time and effort to compromise them to attempt malicious activities. SPF synchronizes with DNS to ensure only authorized entities can send emails from a particular domain.

Otherwise, cyberactors can exploit your brand name by sending fraudulent and spam emails, asking receivers to click a malicious link, download a corrupted file, or share sensitive details. In many cases, they even request for direct money transfer in your business’s name.

Once you’re all set up with your DNS record for SPF, don’t forget to check it using our free SPF checker tool to test its validity!

About
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Ahona Rudra

Domain & Email Security Expert at PowerDMARC

Ahona is the Marketing Manager at PowerDMARC, with 5+ years of experience in writing about cybersecurity topics, specializing in domain and email security. Ahona holds a post-graduation degree in Journalism and Communications, solidifying her career in the security sector since 2019.

What is SPF Record in DNS?