A large mobile telephony and data network operator has a data that houses network elements. These are essentially large computers running on Linux. The perimeter of the data center is secured with fir

Hardening network elements with strong user credentials and conducting regular security assessments applies the principle of defense-in-depth, ensuring that if perimeter defenses are breached, internal systems are not trivially compromised. Linux-based network elements have their own attack surface including SSH services, local accounts, and running processes that must be secured regardless of firewall protection. Regular security testing validates that hardening measures remain effective over time.

Physical access restrictions alone do not protect against network-based attacks that can reach internal systems through legitimate data center connectivity.

Firewalls and IPS systems are perimeter controls that can be bypassed or misconfigured - relying solely on them violates the principle of defense-in-depth.

Accepting attacks as inevitable and relying only on a backup site is a reactive posture that ignores preventive hardening, which is a fundamental security failure.