Which applications typically use a MID server?

The MID server plays a crucial role in facilitating communication between ServiceNow instances and external applications or systems. It acts as a bridge that enables the ServiceNow platform to securely access resources within an organization's firewall or remote systems.

The use of the MID server is not limited to just Discovery (often abbreviated as Disco), but also extends to various system web services that require interaction with external applications and data. This includes but is not limited to integrations with third-party applications, orchestrations, and other functionalities that depend on communicating across a secure channel.

By utilizing the MID server for Disco and other system web services, organizations can enhance their integration capabilities, ensuring data can flow between their ServiceNow instance and various external services or systems efficiently and securely. This comprehensive usage highlights the versatility of the MID server beyond just Discovery functions, which is why it serves as the correct answer in this context.