- Restricted Address
- Function: Allows incoming calls only from specific, pre-approved addresses.
- Security Focus: Authenticates the node (the device or location) rather than the individual user.
- Use Case: Suitable for environments where only certain locations should be allowed access.
- Callback
- Function: The user initiates a connection by supplying an identifying code, and the system responds by calling back to a predetermined telephone number.
- Security Focus: Adds a layer of security by verifying the connection through a known, trusted telephone number.
- Limitation: Less effective for users who frequently travel, as it requires a fixed callback number.
- Caller ID
- Function: Checks the incoming telephone number against an approval list before using the Callback feature.
- Security Focus: Ensures that the call originates from an expected location before establishing a connection.
- Limitation: Similar to Callback, it is less useful for users who are on the move and may not be calling from a recognized number.
These technologies are designed to enhance the security of remote access by verifying the origin of the connection, though they may have limitations for users requiring flexible access from multiple locations.