Email continues to be the single biggest entry point for cyberattacks, and that isn’t changing in 2024. What is changing is how businesses protect their users — and whether separate Secure Email Gateways are still needed in a Microsoft 365 world.
For years, Secure Email Gateways (SEGs) were the default solution for filtering threats, blocking spam, and catching phishing attempts. But with more organizations moving entirely to Microsoft 365, the conversation is shifting: do SMBs still need a separate email gateway, or are Microsoft’s native cloud controls strong enough on their own?
This question is coming up constantly across South Georgia and North Florida — especially for businesses trying to tighten security without adding unnecessary complexity or cost. The honest answer: it depends on your environment, your risks, and how well your cloud tools are configured.
Why SEGs became popular in the first place
Before cloud email became dominant, SEGs were the reliable way to filter threats before they reached your mail server. They sat in front of Exchange, scanned inbound and outbound messages, and blocked malware and spam long before Microsoft had the native capabilities it has today.
SEGs worked — and many still do — but they were built for a different era. Today, most businesses store their entire email environment in Microsoft 365, which changes how the threat landscape works and how email security needs to be designed.
Native cloud controls have come a long way
Microsoft 365 now includes advanced layers of protection that didn’t exist a few years ago, including:
- Defender for Office 365 with phishing and impersonation protection
- Safe Links and Safe Attachments for URL and file scanning
- Zero-hour auto purge for emerging threats
- AI-driven anomaly detection
- Continuous improvements based on global threat intelligence
These native controls don’t just filter email — they integrate directly with identity security, endpoint controls, and Conditional Access. That creates a much broader defense strategy than a traditional SEG can offer on its own.
Where SEGs still have an edge
Even in 2024, SEGs can be useful when businesses need:
- strict regulatory filtering
- detailed outbound email inspection
- advanced data loss prevention (DLP) beyond Microsoft’s baseline
- complex routing requirements
- layered protection across multiple domains or hybrid systems
Some industries — like financial institutions and government agencies — may prefer the extra visibility and rule customization a SEG provides, especially during audits or for very specific compliance requirements.
Where Microsoft 365 outperforms traditional gateways
For most SMBs, Microsoft 365’s native controls provide stronger real-world protection because they’re tightly integrated with identity security.
Attackers now focus heavily on:
- phishing aimed at Microsoft 365 logins
- OAuth app abuse
- token theft and session hijacking
- impersonation inside Teams, SharePoint, and email
- business email compromise (BEC) using existing accounts
SEGs typically don’t see this behavior because it happens inside the cloud tenant. Microsoft Defender does.
This is why many organizations are choosing to retire their SEGs and rely fully on cloud-native controls — especially when paired with Conditional Access, MFA, and proper tenant hardening.
What SMBs should take away in 2024
The decision isn’t simply “SEG or Microsoft 365.” It’s about choosing what aligns with your risk level, your budget, and your operational model.
For most SMBs:
A well-configured Microsoft 365 tenant with Defender for Office 365 provides excellent protection — often better than layering on an external gateway, especially when identity and access controls are tuned correctly.
For higher-risk environments:
A SEG can still offer value, particularly where extra outbound filtering, stricter compliance rules, or complex routing is required. The key is making sure your email defenses match the way attackers operate today — not the way they did a decade ago.
Not sure if you still need a Secure Email Gateway?
NTS helps SMBs across South Georgia and North Florida evaluate whether to keep, replace, or retire SEGs — and how to get the most from Microsoft 365’s native security stack. We’ll review your current setup and give you a plain-language recommendation.