Protect Your Brand and Your Inbox: A Guide to Email Security and Deliverability
Proper domain configuration and broader email security measures are frequently overlooked by many IT and marketing professionals, despite their critical importance. Email remains a vital communication channel for businesses, yet its security and deliverability are increasingly under threat. IT Managers, Cyber Security Officers, Heads of IT, and Marketing Managers face stiff challenges ensuring emails reach their intended audience securely and reliably. Implementing robust domain configurations (email authentication) such as Domain-based Message Authentication, Reporting and Conformance (DMARC), Sender Policy Framework (SPF), and DomainKeys Identified Mail (DKIM) is essential, not only to prevent spoofing and phishing but also to maintain high deliverability rates for transactional and marketing emails.
The Dual Challenge: Domain Configuration and Email Security
Email authentication protocols like DMARC, SPF, and DKIM form the foundational domain configuration necessary for secure email communications. Properly configured domains ensure authenticity, reduce phishing risks, and enhance deliverability.
According to Check Point, “Emails contain various headers that provide useful information about the email, and among these are headers stating who the sender of the email is. While these fields are auto-populated by email programs, it’s possible to modify their content, and email spoofers take advantage of this fact to pretend to be someone else.”
Check Point also notes that email authentication protects an organisation’s brand, customers, employees, and partners from spoofing attacks by proving that every email using its domain actually came from a legitimate sender.
However, email authentication is only one part of the wider email security ecosystem. The larger aspect of email security involves comprehensive filtering and threat prevention. This includes scanning email content for malicious links, detecting phishing attempts, and sandboxing attachments to ensure they are not harmful. It ensures users are not redirected to malicious websites or allowed to download dangerous file types such as executable files.
Endpoint protection also plays a key role in this ecosystem by acting as the last line of defence—monitoring user behaviour and blocking malware that may get through email filters.
The consequences of poor email management include:
- Lost sales opportunities due to emails landing in spam
- Customer dissatisfaction from missed transactional communications
- Financial and reputational damage from phishing and spoofing attacks
It is important to note that spoofing attacks are primarily outbound in nature—attackers forge your domain name to send fraudulent emails to others. For example, a common impersonation attack involves an email appearing to come from a line manager, instructing an employee to urgently purchase gift vouchers. Without proper authentication measures in place, these spoofed emails can bypass detection and cause real damage.
Essential Domain Configuration: DMARC, SPF, and DKIM
DMARC (Domain-based Message Authentication, Reporting & Conformance)
DMARC verifies email authenticity, allowing domain owners to instruct email providers on handling unauthenticated emails, significantly reducing spoofing risks and enhancing deliverability. DMARC also defines how recipients should handle failed checks, from quarantining to rejecting suspicious messages outright.
SPF (Sender Policy Framework)
SPF specifies the IP addresses that are permitted to send emails on behalf of a domain. It helps verify that emails come from trusted servers, as part of the DNS record.
DKIM (DomainKeys Identified Mail)
DKIM adds a layer of authentication by enabling email messages to be digitally signed. These signatures prove the message came from an authorised sender and was not modified during transit.
Together, these protocols form a free and powerful way to protect against email spoofing.
New Compliance Requirements by Major ESPs
From 5th May 2025, Microsoft will enforce DMARC, SPF, and DKIM compliance for domains sending over 5,000 emails daily. Google and Yahoo have already implemented similar stringent authentication controls since 2024, significantly increasing the risks of emails being rejected or marked as spam for non-compliant domains.
Organisations sending fewer than 5,000 emails per day also face risks without proper compliance. Poorly authenticated emails frequently end up in spam folders, reducing visibility and engagement for marketing campaigns and essential service communications.
Expert Insight
Jean-Luc Oudart, IT Architect for CommSec, states, “Correct domain configuration for email is essential to prevent spoofing of your company email addresses, stop phishing emails from reaching inboxes, and ensure your outbound emails don’t get rejected or put into spam or junk folders.” He further emphasises, “Poorly configured email domains send a signal to hackers that other areas of your IT estate may also be vulnerable to attack.”
Check Your Current Email Configuration
Free online tools can help determine if your email configurations are correct or expose you to phishing risks or email penalties. Some recommended free tools include:
Regular checks can ensure your domain remains secure and emails reach inboxes effectively.
Automated Solutions via CommSec: Securing and Enhancing Email Delivery
CommSec offers comprehensive solutions that:
- Quickly implement and integrate with various email providers
- Provide real-time monitoring and proactive threat detection
- Simplify email compliance and reporting processes
- Ensure comprehensive authentication to improve email deliverability
Automation simplifies compliance management, enhancing email deliverability and protecting against threats like spoofing and phishing.
Partner with CommSec for Robust Email Security and Optimal Deliverability
CommSec’s experienced team helps organisations:
- Conduct detailed email security and deliverability assessments
- Implement and manage DMARC, SPF, and DKIM effectively
- Strengthen email privacy through protocols such as TLS-RPT and MTA-STS
- Improve brand trust and visibility using BIMI
With CommSec, achieving secure, reliable, and efficient email communication is straightforward.
Act Now to Secure Your Email Communications
Ensure your emails consistently and securely reach your intended recipients. Contact CommSec today to safeguard your email security and enhance deliverability.