A Linux security administrator is attempting to resolve performance issues with new software installed on several baselined user systems. After investigating, the security administrator determines…

When SELinux is in enforcing mode, it actively denies any operation not explicitly permitted by the loaded policy. If the installed software requires file, network, or IPC access that is not defined in the existing policy, SELinux silently blocks those operations, causing the software to fail during initialization or execution - exactly the behavior described, without producing obvious error messages that point to SELinux as the cause.

SELinux in enforcing mode with no policy at all would block virtually every operation on the system including basic OS functions, causing catastrophic system-wide failure rather than the targeted failure of only the new software.

A disabled SELinux does not enforce any access controls, so software would run freely regardless of the policy configuration - this would not cause the initialization failures described.

SELinux in permissive mode logs policy violations as AVC denials but does not block operations, so the software would still initialize and execute even if the policy were misconfigured.