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Decoding SPF, DKIM, and DMARC
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Decoding SPF, DKIM, and DMARC

Are you an email marketer who isn’t sure what authentication is and why it’s important in email deliverability? Well, you are not the only one!
The email authentication process can confuse many of us, but we will try to break it down for you to make everything easier to understand in this blog.
So, let’s get started!
Authentication is required for various kinds of transactions. Whether you’re a patient in need of treatment, a driver in need of a license, or anyone else, you must confirm and prove your identity to proceed with the process.
And same goes for the world of email deliverability. You must prove that you are a valid sender to get through via ISP (Internet Service Provider) filters.
SPF, DKIM, and DMARC are terms for server authentication and ensuring that the sender is authorized to send out emails. These three phrases prove that a sender is a real person who has been sending emails from their own domain rather than pretending to be someone else.
All mail systems have grown careful and stricter regarding the types of emails they accept. As a result, having SPF, DKIM & DMARC in check will ensure that emails get sent rather than being rejected entirely.
Let’s try to understand them better.
What exactly are SPFD, DKIM, and DMARC?

What is SPF?

The Sender Policy Framework, or SPF, is an email validation system for detecting and blocking email spoofing. It enables mail exchangers to validate the domain incoming mail from a specific domain originates from an IP address.
An SPF record is a TXT record in the Domain Name System or DNS that specifies which IP addresses and servers are permitted to send mail “from” that domain.
ISPs check the message’s Return-Path domain after it has been transmitted. The next check is to see if the IP address that sent the email matches the IP address given in the Return-Path domain’s SPF record. If this is the case, the message will be delivered after SPF authentication is confirmed.

Why is SPF Important?

SPF stands for Sender Policy Framework, and it’s a recommended standard for protecting email subscribers from spammers. Because fake sender’s addresses and domains are commonly used in email spam and phishing, posting and verifying SPF data is considered one of the most reliable and simple anti-spam strategies.
A spammer may try to send an email from your domain to profit from your good sender reputation. However, properly and appropriately configured SPF authentication will notify the receiving ISP that while the domain may be yours, the transmitting server does not have the authorization to send mail for your domain.
SPF informs incoming mail servers that a message has been sent from a domain that has been authorized by the domain listed.
For example, if an imposter sends an email claiming to be from, the subscriber’s incoming mail server can check if it came from a Facebook-approved server. If it isn’t, then the message wouldn’t be delivered.

What exactly is DKIM?

DKIM, also known as Domain Keys Identified Mail, is an email authentication method that allows the receiver to verify that an email was sent and authorized by the domain’s owner. This is done by adding a digital signature to the email, and this DKIM signature is included in the message as an encryption-protected header.
When a receiver (or receiving system) finds that an email is signed with a valid DKIM signature, it can be sure that components of the email, such as the message body and attachments, haven’t been altered or modified.
DKIM signatures are usually not visible to end-users because the validation is done on the server. Using the DKIM standard will increase email deliverability even more if you combine DKIM records with DMARC and SPF.
DKIM is a TXT record signature that helps the sender and receiver establish confidence.

Why is DKIM important?

DKIM protects recipients from phishing attacks and prevents spammers from doing malpractices. As a result, your email delivery increases, and it grows the stakeholder’s trust.
For example, a retailer sends out an email campaign to promote a new product range. Messages tagged as spam or not delivered to intended recipients will not be distributed without verification, causing the enterprise to lose business.
Spammers can use the chance to create their phishing emails based on the campaign, which increases the risk of customers being confused.
DKIM in email delivery is employed to prove that:
  1. An email’s content has not been altered.
  2. The email’s headers haven’t changed as the original sender sent them.
  3. The email’s sender owns or approves the domain’s owner to use the DKIM domain.
DKIM is a digitally-encrypted signature that can be used to ‘sign’ an email. In an email message, this signature appears as a header.
For example: If someone sends an email claiming to be from, the subscriber’s incoming mail server can check Facebook’s digitally-encrypted signature to see if it came from their server or not. If not, then the mail will be blocked or will not be delivered.
(Note* The header will indicate whether the DKIM signature is authentic or not.)

What is DMARC?

DMARC, or Domain-based Message Authentication, Reporting, and Conformance is a mechanism that determines the validity of an email message using the Sender Policy Framework (SPF) and Domain Keys identified mail (DKIM).
Internet Service Providers (ISPs) can use DMARC records to avoid harmful email practices like domain spoofing and phishing for recipients’ personal information.
So, basically, it lets email senders decide how to handle emails that haven’t been validated with SPF or DKIM. Senders can send those emails to the spam bin or have them altogether blocklisted.
Through DMARC, ISPs can better identify spammers and prevent malicious emails from being sent into consumer inboxes. And doing so can reduce false alarms, improve authentication, and bring transparency in email deliverability practices.
There are three policies to choose from when setting up a DMARC record. These policies tell the receiving server how to handle non-DMARC-compliant mail from you.
  • None: Treat all mail sent from your domain as if DMARC hadn’t validated it.
  • Quarantine: The receiving server may accept the message, but it should be delivered to a location other than the recipient’s inbox (usually, the spam folder)
  • Reject: The message is completely rejected.
DMARC is based on SPF and DKIM, and it ensures that when an email is received, the information in both records matches the domain server. Identifier alignment is another name for this.
For example, when someone tries to send an email claiming to be from, the subscriber’s receiving mail server checks to see if both SPF and DKIM protect the message. It instructs the recipient mail server what to do if neither authentication method works.

How SPF, DKIM & DMARC are related?

DKIM, SPF, and DMARC are email authentication protocols supporting different aspects of the process.
  • SPF: Senders can use SPF to specify which IP addresses are allowed to send mail for a specific domain.
  • DKIM: It gives an encryption key and a digital signature that ensures an email message was not faked or tampered with.
  • DMARC combines SPF and DKIM authentication protocols into a single framework, allowing domain owners to specify how an email from their domain should be handled if an authorization test fails.
Have something more to add? Or did we miss anything? Let us know in the comments below.