What is a callback in networking security?

A callback in networking security refers specifically to a modem-based authentication system in which a user's connection to a network is monitored to ensure secure access. Here's how it typically works: when a user attempts to connect to a network, they provide their credentials, and the system may connect the user back after verifying their identity by hanging up and calling back on a predetermined phone number. This method adds an additional layer of security by ensuring that only authorized users can access the network, as the callback process typically requires the connection to originate from a trusted source.

This method is particularly useful in securing remote access methods and ensuring that potential attackers cannot easily impersonate legitimate users. It is a proactive approach to reducing unauthorized access and enhancing the overall security posture of an organization.