Email Sender Authentication SPF DKIM Explained

The number of emails sent and received stood at 
361 billion in 2024. Despite a surge in social media platforms, emails remain a preferred format for marketing teams as they give direct access to customers.

Email fraud is on the rise. 
Business Email Compromise is one of the leading examples of fraud in which fraudsters trick the customer into believing they are from a trusted sender and cheat them.

The industry uses email authentication to confirm the sender’s identity. With this, spammers and frauds cannot impersonate you, and the customers will trust your emails. Authentication also enhances your email deliverability by assuring Internet Service Providers about your identity.

When your team sends emails, the receiver server tries to authenticate your email address. When it is satisfied, it forwards the email to the inbox. Otherwise, it sends it directly to the spam folder or discards it from the server.

What is Email Authentication?

80-95% of cyber attacks start with a phishing attack. Phishing occurs when a cybercriminal sends you an email disguised as a familiar individual, attempting to deceive you into revealing financial information.

Email servers, such as MassMailer, safeguard against such attacks by verifying that an email originates from a trusted source. This technical solution confirms the sender’s authenticity, ensuring that the email does not come from an unsecured address.

How does Email Authentication Work

At a higher level, there are three steps your organization must take to authenticate that an email is legitimate and coming from you.

Step 1:

Your organization has to establish a few rules. The next step is configuring and publishing those rules in the public domain.

Step 2:

When you or any of your team members send an email, the receiver server will check the rules available publicly. The server does it to authenticate the sender.

Step 3:

Based on your rules like email signature, email header, etc., the server will determine whether it is coming from a trusted source. If yes, it will forward the email to the sender. If it cannot identify the source, it will forward the mail to the spam or junk folder. 

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Two common authentication protocols to avoid email phishing are SPF and DKIM. Let us understand what they are and how
MassMailer can help you to authenticate yourself.

 

What is SPF?

SPF or Sender Policy Framework is a simple TXT file in which your organization specifies a list of IP addresses or mail servers that can send emails from your domain. The receiver’s server uses this list to authenticate your emails and verify that they are really coming from you and not imposters.

How does SPF Work?

• The domain owner or your organization has to set up an SPF record in the Domain Name System (DNS). A DNS is like a phonebook of the internet. Computers do not identify each other through the commonly used domain names such as www.example.com. Instead, they use IP addresses such as 192.168.1.1. When you send an email, this information resides in the email header.

• This SPF record lists approved mail servers and IP addresses that can send emails on behalf of the domain.

• When you or your team sends an email, it carries an IP address and a sender domain.

• The recipient’s mail server queries your domain DNS to check its SPF record.
• It does a quick check to verify whether the IP address of the sending server is in the list of authorized servers.

• If the email is from an authorized server, it passes the authentication. It means the email gets forwarded to the receiver’s inbox.
• If the email is from an unauthorized source, it fails authentication. In that case, the server can perform any of these functions.
  • Mark it as spam and move it directly to the spam folder.
  • Reject the email outright and do not send it to the receiver’s inbox.
  • Quarantines the mail or sends it to the junk folder.

A simple way to understand SPF is to send a letter on the company letterhead. It is a way to ascertain that the letter is from a trusted source. When you also add a return address, it further adds to the receiver’s trust that the letter is legitimate.

MassMailer can help you set up SPF by providing a predefined SPF record that includes its email-sending servers. All you have to do is to add this SPF record to your DNS. If you already have an SPF record, MassMailer helps you update it without interrupting your email setup.