Exchange Server SE – Do You Still Need an On-Premises Email Solution?

Next year, Exchange Server will turn 30, a remarkable milestone for a platform that was often prematurely declared obsolete. The fact is: email remains an indispensable means of communication. According to CloudHQ's Email Statistics report, the number of global email accounts is expected to rise from approximately 4.8 billion today to over 5.6 billion in the next few years. Today, over 392 billion emails are sent daily, and by 2030, this number is expected to grow to over 500 billion. So, the question is not whether email will remain relevant.  

The crucial question is: Where will the necessary infrastructure be operated in the future – locally or exclusively in the cloud?

Is Exchange Server still necessary? 

The adoption of cloud services continues to rise across various industries. Small businesses are leveraging Exchange Online exclusively to take advantage of its flexibility and reduced administrative burden. In contrast, larger organizations often implement hybrid configurations, integrating on-premises Exchange environments with Exchange Online. This approach enables flexible provisioning of mailboxes while maintaining seamless connectivity between local and cloud-based resources. 

If you operate or plan a hybrid scenario, you will continue to need local Exchange servers. This is the only way to ensure clean communication with Exchange Online and stable internal email delivery, without the added complexity of workarounds. 

Why hybrid remains a good option 

Local Exchange servers offer technical capabilities that a pure cloud solution cannot always provide. Typical requirements include: 

• Mailboxes with special protection requirements, e.g., for sensitive HR data or health information. 

• Application mailboxes that are required for sending or receiving emails in internal processes. 

• SMTP relay for applications, devices, or systems that need to deliver messages reliably. 

• Environments without direct internet access, such as production networks or secure segments. 

Hybrid environments provide maximum flexibility: mailboxes and workloads can be operated where they are best suited from a technical and organizational perspective. 

Risks and best practices 

However, operating Exchange servers on-premises comes with responsibility. The platform is very flexible, which allows for numerous scenarios, but it is precisely this flexibility that harbors risks. Any deviation from Microsoft's recommended preferred architecture increases complexity and thus potentially also the attack surface. There are no new components for the Exchange Server SE preferred architecture compared to Exchange Server 2019. The documentation provides an extensive description of the recommended components and configuration. The summary is, keep it as simple as you can. Even virtualization adds an unnecessary layer of complexity.  

If you run Exchange locally, security best practices are not optional guidelines; they are mandatory requirements. This is the only way to ensure that your environment functions reliably and securely. The Exchange Server security best practices include: 

• Deactivate SMB v1 

• Configure download domains 

• Activate Windows Extended Protection 

• Activate HTTP Strict Transport Security (HSTS) 

• Certificate-based signing of PowerShell payload 

• Usage of Exchange Emergency Mitigation Service 

• Configure Exchange TLS best practices by using only TLS 1.2+ and secure cipher suites 

• Activate P2 FROM email header protection 

End of support for Exchange 2016/2019 – what now? 

Support for Exchange Server 2016 and 2019 will end on October 14, 2025. Microsoft is providing a transitional solution through the Extended Security Update Program, but only for a limited period of six months. This program is intended to secure migrations, but not to enable a permanent "business as usual" scenario. 

The long-term solution is Exchange Server Subscription Edition (SE), which has been available since July 1, 2025. You can install Exchange Server SE via an in-place upgrade from Exchange 2019 CU14 or CU15. The process is similar to installing a cumulative update and does not require a complete reinstallation or migration of the databases. New features are announced for CU1 and CU2 – updating now lays the foundation for a stable future. 

Exchange Monitoring – the underestimated must-have 

Whether you have a hybrid or purely on-premises environment, without consistent Exchange monitoring, you are operating your Exchange servers blind. Problems such as slow mail delivery, growing storage loads, or security vulnerabilities are often only noticed when they have already begun to affect operations. 

Professional monitoring provides the transparency you need and enables you to take proactive action before failures occur. ENow offers a Microsoft Exchange Monitoring software solution that combines Exchange monitoring and reporting in a single, clearly structured interface. It delivers all relevant information in real time, without unnecessary complexity. This allows you to identify risks early on, take targeted action, and ensure that your Exchange infrastructure remains stable and secure. 

Conclusion 

Exchange Server is not going away, it is evolving. If you use hybrid scenarios, you will continue to need local Exchange servers in the future. At the same time, requirements are increasing: security standards must be met, architectures must be implemented cleanly, and systems must be continuously monitored and maintained. With a solution like ENow Monitoring for Exchange, you can efficiently monitor your environment and ensure that Exchange continues to run smoothly in the future. 

Additional Resources 

• Exchange 2019 preferred architecture (applies equally to Exchange Server SE)  
• Security best practices for Exchange Server 
• Exchange Server Subscription Edition (SE) is now available
• Announcing Exchange 2016 / 2019 Extended Security Update program 
• ENow Exchange Monitoring and Reporting 

Ensure Your Exchange Environment Stays Secure, Stable, and Compliant

Operating Exchange on-premises or in a hybrid configuration brings flexibility, but also complexity and risk. Without proper monitoring, small issues can escalate into major disruptions. ENow’s Exchange Monitoring & Reporting tool is purpose-built to give IT teams the real-time visibility they need across both hybrid and on-prem environments. With intuitive dashboards, proactive alerting, and deep reporting capabilities, ENow helps you stay ahead of performance bottlenecks, security threats, and configuration drift, without added overhead.

👉Learn how ENow simplifies Exchange monitoring and helps you run a tighter, more secure environment