Which of the following is NOT a feature of MikroTik RouterOS?

MikroTik RouterOS is well-known for its numerous features designed for network management, including VPN services, an OS-level firewall, and hotspot implementation. These features are integral components that enhance security, connectivity, and user management within networking environments.

Email service, however, is not a feature that RouterOS provides. Unlike many server operating systems that include email services as part of their offerings, RouterOS focuses on routing, firewall capabilities, bandwidth management, and other networking functions, leaving email services to other dedicated applications or platforms. Thus, identifying email service as not being a feature of MikroTik RouterOS is accurate and reflects the specialized nature of RouterOS as a networking-focused operating system.