Email is the backbone of modern business communication, with nearly 350 billion emails sent daily. However, this widespread reliance on email also makes it a prime target for cyber threats. Phishing, business email compromise (BEC), and email spoofing are among the most common attacks, often leading to credential theft, financial fraud, and data breaches.

To mitigate these risks, organizations implement email security protocols and policies that govern how emails are sent, received, and protected. Understanding email protocols—such as SMTP, IMAP, and DKIM—is essential for securing email communication and preventing cyber threats. This glossary page explores different types of email protocols, their benefits, and best practices for implementing a corporate email security policy that strengthens an organization's defenses.

A corporate email security policy establishes guidelines to protect an organization’s email communications from cyber threats. It outlines security measures to prevent phishing, data breaches, and unauthorized access.

An effective policy should address:

• Authentication: Implementing SPF, DKIM, and DMARC to verify sender legitimacy and prevent spoofing. ‍
• Encryption: Using TLS and end-to-end encryption to secure email content in transit and at rest. ‍
• Email protocols: Enforcing secure use of SMTP, IMAP, and POP3 to prevent unauthorized email access. ‍
• Access controls: Restricting email account access with multifactor authentication (MFA). ‍
• User awareness: Training employees to recognize phishing attempts and suspicious emails.

Adopting email security policy best practices strengthens an organization’s defenses against evolving threats. Learn how AI-driven email security can enhance protection: Looking beyond secure email gateways with the latest innovations to Darktrace/ EMAIL.

Implementing robust email protocols as part of a corporate security policy offers several key benefits, helping organizations safeguard communications and maintain operational efficiency.

1. Protection from security threats

Email remains a primary attack vector for phishing, malware, and business email compromise (BEC). Protocols like SPF, DKIM, and DMARC authenticate senders, reducing spoofing and fraudulent emails. Encryption ensures email content remains secure, preventing unauthorized access.

2. Compliance with regulations

Regulatory frameworks like GDPR, HIPAA, and SOX require businesses to implement secure communication practices. Proper email protocols help organizations meet compliance standards, avoiding legal and financial penalties.

3. Data protection

Email security protocols safeguard sensitive data, preventing unauthorized interception, leaks, and breaches. TLS encryption ensures messages remain confidential during transmission, while policies like Data Loss Prevention (DLP) restrict unauthorized sharing of sensitive information.

4. Improved productivity

Secure email protocols reduce spam, phishing attempts, and malicious content, allowing employees to focus on critical tasks. Automating threat detection and email filtering minimizes disruptions caused by security incidents.

5. Safeguarding business reputation

A cyber-attack or data breach can damage trust with customers and partners. Implementing strong email protocols enhances credibility by ensuring secure, authenticated communication and reducing the risk of brand impersonation.

6. Reduced financial risk

By mitigating email-based threats, businesses avoid costly security incidents, downtime, and regulatory fines. Investing in proactive security measures minimizes financial losses tied to cyber threats.

Developing an email security policy with strong protocols ensures long-term resilience against evolving threats, strengthening both security and business operations.

Email communication relies on multiple protocols to send, receive, and secure messages. Understanding these email security protocols is essential for protecting business communications from cyber threats.

1. Simple Mail Transfer Protocol (SMTP)

Purpose: SMTP is an email protocol used to send messages from a client to a mail server or between mail servers. It works by transferring email data over the internet using TCP/IP.

How it works:

• When an email is sent, SMTP routes it from the sender’s email client to the recipient’s mail server.
• It typically operates on ports 25, 465 (SSL), and 587 (TLS) for secure transmission.

Why businesses need it: SMTP is essential for outgoing email communication and should be combined with authentication measures like SPF, DKIM, and DMARC to prevent spoofing.

2. Post Office Protocol v3 (POP3)

Purpose: POP3 is an email protocol used to retrieve emails from a mail server to a local device.

How it works:

• Emails are downloaded from the server and usually deleted from the server afterward.
• Operates on ports 110 (unencrypted) and 995 (SSL/TLS encrypted).

Why businesses may use it: POP3 is suitable for users who want offline email access but is less ideal for businesses needing multi-device access to emails.

3. Internet Message Access Protocol (IMAP)

Purpose: IMAP allows users to access and manage emails directly on a mail server without downloading them.

How it works:

• Emails remain stored on the server, and users can access them from multiple devices.
• Operates on ports 143 (unencrypted) and 993 (SSL/TLS encrypted).

Why businesses need it: IMAP is ideal for modern workplaces that rely on remote access and multiple-device synchronization.

4. DomainKeys Identified Mail (DKIM)

Purpose: DKIM authenticates email senders and ensures message integrity by adding a cryptographic signature to outgoing emails.

How it works:

• The sender’s mail server generates a digital signature in the email header.
• The recipient’s mail server verifies the signature against the sender’s domain records.

Why businesses need it: DKIM prevents email tampering and impersonation attacks, ensuring emails are trustworthy.

5. Domain-based Message Authentication, Reporting & Conformance (DMARC)

Purpose: DMARC builds on SPF and DKIM to prevent email spoofing and phishing attacks.

How it works:

• It enforces policies on how email servers should handle messages that fail authentication.
• It provides reports on email authentication status, helping organizations monitor spoofing attempts.

Why businesses need it: DMARC strengthens email security protocols by preventing unauthorized domain use. However, it has limitations, requiring additional AI-driven security for full protection. (Learn more: Beyond DMARC: Navigating the Gaps in Email Security)

Choosing the right protocols for business

Organizations should implement SMTP, IMAP, DKIM, and DMARC for a secure, efficient email system. While POP3 is less common for business use, ensuring proper email security protocols helps protect against evolving threats.

Darktrace's platform offers cutting-edge AI solutions specifically designed to enhance email security. By integrating technologies like DKIM with Darktrace's sophisticated cybersecurity measures, organizations can achieve unparalleled protection against email threats. Discover the advantages of AI for cybersecurity and safeguard your emails with Darktrace. Learn more about our email solutions and how they can benefit your organization by visiting Darktrace's website.