On *BSD kernels you can use securelevel to achieve proper immutability to some extent (like unchangeable pf rules, read-only raw disk devices, etc...). Disablin

On *BSD kernels you can use securelevel to achieve proper immutability to some extent (like unchangeable pf rules, read-only raw disk devices, etc...). Disabling ssh only gives you the guarantee that ssh is going to be disabled, and that is quite different from immutability.