What is an effective method for ensuring secure connectivity in network design?

Using strong encryption for data in transit is an effective method for ensuring secure connectivity in network design because it protects the integrity and confidentiality of data as it travels across the network. Encryption helps to prevent unauthorized access and eavesdropping, thus ensuring that sensitive information remains secure, even if it is intercepted during transmission. This is crucial in environments where data must be transmitted over public or shared networks, as it mitigates various threats, including man-in-the-middle attacks.

While disabling all unused ports is a necessary practice to reduce the attack surface, it does not directly address the protection of data in transit. Similarly, implementing intranet-only applications may improve security by limiting access, but it does not encrypt data transmitted between users and the applications. Exclusively mapping user permissions is an important aspect of access control but does not secure the actual data being transmitted over the network.

In network security, the encryption of data in transit is paramount, especially for organizations that handle sensitive information, making it the most effective method among the given options for ensuring secure connectivity.