Email Security Protocols and Why They’re Important

Despite the proliferation of messaging platforms, email remains the number one communication and verification method worldwide. In 2024, there were 4.48 billion email users worldwide, accounting for 56.8% of the world’s total population with projections indicating annual growth. Unfortunately, due to its popularity, email communications have long attracted a nefarious crowd: the cybercriminal.

Despite long-established countermeasures, email-based threats have only intensified, both in sophistication and frequency. In a report published by Cybercrime Magazine, researchers found that ransomware attacks occur every two seconds, placing annual damage cost projections at $57 billion for 2025 – approximately $4.8 billion monthly. Phishing remains the most common form of cyber crime, with an estimated 3.4 billion spam emails sent every day. 

But phishing isn’t the only way cyber criminals gain access to sensitive information. According to IBM, Business Email Compromise (BEC) attacks are the second most expensive type of security breach, costing an average of $4.89 million annually. Given the substantial damage these attacks can cause, it’s crucial for users to equip themselves with the proper tools to combat such threats.

Email security protocols are designed to protect against these threats by verifying sender authenticity, encrypting content, and filtering out malicious messages. The good news is that most major email providers automatically implement these protocols to protect their users. 

However, if you use an Email Service Provider (ESP), your DMARC responsibilities depend on your setup:

• Sending from your own domain: You’re responsible for publishing DMARC, SPF, and DKIM DNS records. While your ESP provides the necessary DKIM key and SPF include statement, you must add these to your domain’s DNS and create/manage your DMARC policy record yourself.
• Using ESP’s domain: The ESP handles all DMARC management for their domains—no setup required from you.
• DMARC requirements: Major providers like Google and Yahoo now require DMARC for bulk senders to ensure deliverability and prevent email spoofing.

EasyDMARC offers a streamlined way to implement comprehensive email security, providing protection against spoofing, phishing, and other email-based attacks.

What are Email Security Protocols?

Email security protocols are configurations that help keep email communications safe. Let’s take a look at some of the most common ones:

1. DMARC
2. SPF
3. DKIM
4. MTA-STS
5. TLS-RPT
6. S/MIME
7. BIMI

Protocol	Purpose	How it Works
SPF	Validates authorized sending IPs	Publishes allowed IPs in DNS, mail servers verify before accepting
DKIM	Verifies email content integrity	Signs message headers with a private key, verified with public key in DNS
DMARC	Ties SPF and DKIM results, provides reporting	Instructs receivers what to do if authentication fails
MTA-STS	Forces TLS encryption for incoming emails	Publishes a policy in DNS, rejecting non-TLS mail servers
TLS-RPT	Monitors email encryption issues	Sends reports if email encryption fails
S/MIME	Encrypts email body and attachments	Uses digital certificates for encryption and signing
BIMI	Shows logo in inboxes after DMARC pass	Requires strong authentication and displays brand logo

What is DMARC?

DMARC (Domain-based Message Authentication, Reporting, and Conformance) is an email authentication protocol that helps protect organizations and their recipients from fraudulent emails. Since its initial introduction, it has become a fundamental domain security tool and a global authentication standard. It works by utilizing SPF (Sender Policy Framework) and DKIM (Domain Keys Identified Mail) to determine the authenticity of a message.

For Managed Service Providers (MSPs), implementing DMARC for MSP clients provides critical security value. A regular DMARC lookup process allows MSPs to monitor client domains, prevent email spoofing, and enhance overall security posture. 

DMARC ensures that only authorized senders can use your domain, safeguarding your organization’s reputation and protecting clients and partners from fraudulent emails that appear to come from your email address. It is crucial for defending your domain against phishing and spoofing attacks. Additionally, DMARC reports offer insights into how your domain is being used and help you detect unauthorized activities before they become serious threats.

What is SPF?

SPF (Sender Policy Framework) is an email authentication protocol that lets domain owners specify which IP addresses are authorized to send emails on their behalf.

It prevents spoofing of the RFC5321.MailFrom (Return-Path) address by publishing a DNS record listing these IPs, and receiving servers can validate the sending IP against the SPF record.

SPF results alone usually do not cause direct rejection; instead, they contribute to the overall authentication evaluation (especially when combined with DKIM and DMARC) and may influence spam filtering decisions.

For maximum protection, SPF is often implemented alongside DKIM (DomainKeys Identified Mail), which provides cryptographic verification that messages haven’t been altered in transit.

What is DKIM?

DKIM is a protocol that allows domain and organization owners to send authenticated or signed emails. This verification is made possible through cryptographic authentication.

It allows the recipient server to verify that the content of the original message was not altered in any way, ensuring that an email was properly signed and remains unaltered. It works in tandem with SPF to provide the maximum protection for your domain, ensuring deliverability and helping to reduce the risk of phishing attacks.

What is MTA-STS?

MTA-STS (Mail Transfer Agent Strict Transport Security) is a mechanism that enforces TLS, an email encryption protocol, for inbound email delivery to a domain. It allows mail servers to securely communicate by ensuring messages are transmitted over an encrypted connection, thereby mitigating risks such as man-in-the-middle attacks.

In 2019, Google became the first major email provider to adopt the new MTA-STS policy, which ensures all inbound emails come through the Transport Layer Security (TLS). This policy complements and strengthens STARTTLS, which is a command that allows mail servers to upgrade an SMTP (Simple Mail Transfer Protocol) connection to a secure, encrypted one. The issue with STARTTLS is that it is vulnerable to downgrade attacks and lacks mechanisms for strict enforcement or sender authentication, making it optional and insecure in certain scenarios.

The MTA-STS policy aims to prevent attackers from tampering with email content or sending the communication to another address. Unlike STARTTLS, MTA Strict Transport Security always keeps TLS on. It tells external servers that your email server only accepts email delivery through a secure connection.

What is TLS-RPT?

TLS Reporting (TLS-RPT) is a protocol that allows email domains to receive reports about the success or failure of TLS encryption during email transmission, providing insights into potential security issues when emails are sent to a domain.

Like DMARC reports, TLS reports detail failed SMTP connections and explain why they happened. These failures occur for three reasons:

• Failed TLS negotiation
• DNS-related issues
• MTA-STS problems

Also like DMARC reports, TLS reports are delivered to a particular URI (Uniform Resource Identifier) or email address set up via a DNS TXT record.

While other protocols focus on authentication and preventing spoofing, TLS-RPT is used specifically to help ensure that the transport encryption layer is working properly, protecting message confidentiality during transmission.

What is S/MIME?

S/MIME (Secure/Multipurpose Internet Mail Extensions) provides end-to-end encryption and digital signatures for email messages. Unlike SPF, DKIM, and DMARC, which focus on server-level authentication, S/MIME operates at the individual message level.

Key features of S/MIME include:

1. End-to-end encryption: S/MIME encrypts the actual content of email messages, keeping them private even if intercepted during transmission. Only the intended recipient with the correct private key can decrypt and read the message.
2. Digital signatures: S/MIME allows senders to digitally sign their messages, verifying their identity to recipients and ensuring the message hasn’t been tampered with during transit.
3. Certificate-based: S/MIME relies on public key infrastructure (PKI) and digital certificates issued by trusted Certificate Authorities (CAs). Each user needs their own certificate containing their public key.
4. Client-side implementation: Unlike server-based protocols, S/MIME typically requires configuration on the email client (like Outlook, Apple Mail, etc.) rather than at the mail server level.

What is BIMI?

BIMI (Brand Indicators for Message Identification) is a visual trust indicator that allows domain owners to display their verified brand logos in supporting inboxes after passing DMARC authentication. That way, your customers can be sure that your emails are legitimate.

BIMI is built on the DMARC standard for verifying email. Before you send an email to your recipients’ inboxes, your email provider verifies it against the sender’s DMARC record within the message to confirm that it’s legitimate. Resources like BIMI record checks allow users to validate their BIMI record to ensure customer trust.

Why are Email Security Protocols Important?

Email security protocols, like the ones discussed above, are vital in combating email-related attacks. As such, major email providers including Google, Yahoo, Microsoft, and Apple have begun to require certain authentication protocols like SPF, DKIM, and a proper DMARC setup to protect users from spam, spoofing, and phishing, help keep user data safe, and preserve their brand reputation. 

While these major platforms simply require base-level implementation — meaning a DMARC record with at least a p=none policy — this is just the monitoring mode of DMARC and represents the first step in a domain’s DMARC journey. For the highest level of projection against email-based attacks, it is recommended that users implement a policy of p=reject in order to instruct email receivers to outright reject emails that fail DMARC checks. 

What are Phishing and Spoofing?

Phishing

Phishing is a social engineering tactic in which hackers send emails or other messages pretending to be from reputable sources in order to get individuals to share sensitive and personal information. Since the mid-1990s, cybercriminals have used phishing attacks to steal credentials, financial information, and confidential business data, which often results in financial losses and reputational damage.

Phishing remains the most prevalent cyber threat worldwide, accounting for the majority of security breaches, and is often the entry point for ransomware and BEC scams. 

Spoofing

Spoofing is a type of cybercrime in which spam emails are sent using the identity of a trusted company or individual. Bad actors send fake emails that appear legitimate so they can trick victims into sharing sensitive details or downloading malware-infected files.

Cybercriminals use email spoofing for many reasons, including:

• Hiding their identities
• Avoiding a spam blocklist
• Damaging a brand’s image
• Doing personal damage
• Requesting transfers of money
• Tricking victims into submitting sensitive details like passwords and login credentials
• Fraudulently gaining a target’s financial details or OTPs

How are Phishing and Spoofing Connected?

Phishing attacks are successful because they often use emails designed to look legitimate and appear to come from a trusted sender. These cyberattacks exploit human nature, incorporating elements of urgency, fear, or excitement. 

For example, a phishing email might look like an urgent bank message saying your account has been compromised and you need to submit your login credentials. It could also seem like communication from your boss requesting sensitive info or an email saying you’ve won something and need to click on a malicious link (disguised as a genuine one).

You can avoid phishing attacks by checking if an email is sent from an authentic and credible domain. Other factors like misspellings, unrequested or unidentified links and files, unusual requests, etc., are red flags too.

On the other hand, spoofing involves disguising illegitimate communication as legitimate. Bad actors use anything from email addresses and phone numbers to domain names and websites.

In email spoofing, they usually send emails from a typosquatted or extended email domain. Typosquatting is a cybercrime where malicious actors register domains with deliberate misspellings to lure victims into clicking a corrupt link or sharing crucial details, for example, using amaz0n.com instead of amazon.com. 

Phishing and spoofing are often used interchangeably because they work hand in hand to create a believable email that appears to come from a legitimate source. Hackers use email spoofing tactics to conceal phishing attempts and fool recipients.

Which Security Protocols Help Prevent These Attacks?

DMARC, DKIM, and SPF all specifically help prevent spoofing and phishing. By correctly implementing these protocols, users can correctly authenticate, verify, and monitor email communications.

Email Security Protocols Protect Your Brand

Many organizations view security measures as obstacles that slow down operations and create friction in communication channels. When it comes to email security protocols, there’s often hesitation due to perceived implementation complexity and concerns about potential delivery disruptions. However, this short-term thinking ignores the substantial consequences of email-based attacks. A single successful phishing campaign or domain spoofing incident can lead to data breaches costing millions, regulatory penalties, and most devastatingly, the erosion of customer trust that may have taken years to build.

The reputational damage from compromised email channels far outweighs any temporary inconvenience during security implementation. In fact, 86% of customers are willing to pay more for companies they trust, while one-third of consumers will abandon brands they love after just one bad experience. 

When customers receive fraudulent emails appearing to come from your domain, they don’t blame the cybercriminals – they question your organization’s commitment to security. Modern email authentication protocols not only prevent these incidents but have become streamlined enough that implementation no longer significantly impacts operations, making the argument against email security implementation obsolete.

Protecting Your User’s Data is Critical

The landscape of data leaks has evolved into a persistent threat for businesses of all sizes. According to IBM’s Cost of a Data Breach Report 2023, the global average cost of a data breach reached $4.45 million, a 15% increase over three years. These financial impacts extend far beyond immediately fixable costs. When MGM Resorts experienced a massive breach in September 2023, they reported losses exceeding $100 million from operational disruptions alone, while T-Mobile’s 2021 breach resulted in a $350 million settlement after exposing data from 76.6 million customers.

The repercussions of data leaks stretch well beyond financial statements. Perhaps most concerning is the long-tail effect – businesses typically don’t discover breaches for an average of 277 days, allowing attackers extensive access to sensitive systems.

Email security protocols are the critical first line of defense against these devastating scenarios. Given that approximately 90% of data breaches begin with phishing emails or business email compromise, implementing robust authentication standards like DMARC, SPF, and DKIM serves as a foundational security measure. 

These protocols help prevent attackers from impersonating legitimate domains, blocking one of the most common entry points for data theft. By verifying sender legitimacy and ensuring email integrity, these standards significantly reduce the risk of employees or customers falling victim to sophisticated phishing attempts that often initiate the chain of events leading to catastrophic data exposure.

Implementing Email Security Protocols can be Easy

Email security protocols like SPF, DKIM, DMARC, TLS-RPT, MTA-STS, S/MINE, and BIMI form the foundation of modern communication security. As we’ve seen, email remains the primary communication and verification channel worldwide, with billions of users depending on it daily. As such, email is an attractive target for cybercriminals employing increasingly sophisticated phishing attacks, spoofing, and fraud schemes.

Implementation of these critical protocols doesn’t have to be complex or disruptive when approached proactively. DMARC solutions for businesses are a great way to ensure proper execution of these measures.

At EasyDMARC, we offer a comprehensive platform specifically designed to simplify email security implementation. Our solution provides automated setup, continuous monitoring, and real-time reporting to ensure your domain remains protected without burdening your IT resources. Whether you’re managing a small business email server or enterprise-level communications, our intuitive dashboard and expert support make maintaining robust email security accessible for organizations of all sizes.

As we look to the future, email-based threats will only become more sophisticated, leveraging advanced AI and social engineering techniques to bypass traditional security measures. The rise of deepfakes and machine-learning powered impersonation attacks means that yesterday’s security approaches are insufficient for tomorrow’s threats. By implementing comprehensive email security protocols now, organizations establish a critical first line of defense against evolving threats. 

With EasyDMARC’s continuous updates and proactive security approach, businesses can stay ahead of emerging vulnerabilities, preserve their brand reputation, and ensure the integrity of their most important communication channel.