What aspect of High Availability ensures network access continuity?

Configuring multiple Firebox devices to back each other up is essential for ensuring network access continuity in a High Availability (HA) setup. This configuration involves deploying a primary Firebox and a backup Firebox that can take over the responsibilities of the primary device if it fails. This redundancy means that in case of a hardware failure, software issue, or network interruption affecting the primary Firebox, the backup can immediately assume control and maintain the network's operations without any noticeable disruption to users.

This setup is crucial for maintaining consistent service levels, especially for businesses that rely on continuous access to their network resources. Users and services experience virtually uninterrupted access, which is particularly important for critical applications and services that require high uptime.

Meanwhile, the other choices do not directly contribute to continuity of network access in a High Availability scenario. Limiting network resources can actually lead to reduced access rather than continuity. Regularly changing passwords, while an important security practice, does not address redundancy or failover capabilities. Restricting access to critical systems can lead to bottlenecks and doesn’t ensure that the systems remain available during failures. Therefore, the correct approach to achieving network access continuity in a High Availability context is the use of multiple Firebox devices configured to support each other.