Management protocols like NETCONF access network elements on well-known ports. Which design practice hardens a network device implementation?

Specifying the source interface for SSH primarily controls which interface the device uses for outbound SSH connections, not which inbound sources are allowed to connect to SSH.

Limiting access to specific management ports (like 830 for NETCONF), restricting source IP addresses of clients (well-known clients), and securing SSH VTY lines are all fundamental hardening practices to control and secure administrative access to network devices. These measures collectively minimize the attack surface for management protocols.

Enabling Control Plane Policing (CoPP) protects the device's CPU from malicious or excessive traffic, but it does not directly implement access control for management protocols based on source or port.

Configuring 'ip http secure-server' enables HTTPS for web management access, which is a good practice for web interfaces, but it doesn't directly address NETCONF or generic SSH VTY access security.