4.4: Implement and Manage a Firewall on Servers
=========================================================
Implement and manage a firewall on servers, where supported. Example implementations include a virtual firewall, operating system firewall, or a third-party firewall agent.

.. list-table::
	:header-rows: 1

	* - Asset Type
	  - Security Function
	  - Implementation Groups
	* - Devices
	  - Protect
	  - 1, 2, 3

Dependencies
------------
* Safeguard 1.1: Establish and Maintain Detailed Enterprise Asset Inventory
* Safeguard 2.1: Establish and Maintain a Software Inventory
* Safeguard 4.1: Establish and Maintain a Secure Configuration Process

Inputs
------
#. :code:`GV1`: Enterprise asset inventory
#. :code:`GV5`: Authorized software inventory
#. :code:`GV3`: Configuration standard

Operations
----------
#. Identify and enumerate servers capable of hosting a firewall using :code:`GV1` (M1)
#. Identify and enumerate applications capable of hosting a firewall using :code:`GV5` (M2)
#. Using configuration standards to check if firewalls are properly configured
	#. Enumerate servers from Operation 1 with properly configured firewalls (M3)
	#. Enumerate servers from Operation 1 with improperly configured firewalls (M4)
	#. Enumerate applications from Operation 2 with properly configured firewalls (M3)
	#. Enumerate application from Operation 2 with improperly configured firewalls (M4)

Measures
--------
* M1 = Count of servers enterprise assets capable of hosting a firewall
* M2 = Count of applications software capable of hosting a firewall
* M3 = Count of servers with properly configured firewalls
* M4 = Count of servers with improperly configured firewalls
* M5 = Count of applications with properly configured firewalls
* M6 = Count of applications with improperly configured firewalls

Metrics
-------

Implementation of firewalls
^^^^^^^^^^^^^^^^^^^^^^^^^
.. list-table::

	* - **Metric**
	  - | The percentage of properly configured firewalls within the enterprise
	* - **Calculation**
	  - :code:`(M3 + M5) / (M1 + M2)`


.. history
.. authors
.. license