Hello @Chris48,
Based on your description, I'd like to explain that while Microsoft Defender for Endpoint does provide protection for on-premises Exchange servers, it is primarily an endpoint security solution designed to help prevent, detect, and respond to advanced attacks that could compromise your network . threaten. For Exchange specifically, Microsoft offers Exchange online protection, which is designed to protect your email environment. However, it's worth noting that the service is primarily cloud-based and typically requires an internet connection to take advantage of all features, such as real-time updates of the latest threat intelligence. As for the non-networked environment you mentioned, I have no right to recommend third-party software to you. If possible, you can try connecting your environment to the Internet and try Exchange online protection. For specific operations, refer to the following documents:https://www.yisu.com/zixun/25575.html