13.10: Perform Application Layer Filtering
=========================================================
Perform application layer filtering. Example implementations include a filtering proxy, application layer firewall, or gateway.

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

	* - Asset Type
	  - Security Function
	  - Implementation Groups
	* - Network
	  - Protect
	  - 3

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

Inputs
-----------
#. :code:`GV35`: Assets that are part of the network infrastructure
#. :code:`GV5`: Authorized Software Inventory

Operations
----------
#. Use Input 2 :code:`GV5` to identify software used for application layer filtering 
#. For each asset in Input 1 :code:`GV35, determine whether it is covered by at least one sofware identified in Operation 1
	#. Identify and enumerate assets covered by application layer filtering software (M2)
	#. Identify and enumerate assets not covered by application layer filtering software (M3)

Measures
--------
* M1 = Count of network infrastructure assets
* M2 = Count of network infrastructure assets covered by application layer filtering software
* M3 = Count of network infrastructure assets not covered by application layer filtering software

Metrics
-------

Coverage
^^^^^^^^
.. list-table::

	* - **Metric**
	  - | The percentage of network infrastructure assets covered by 
	    | application layering software
	* - **Calculation**
	  - :code:`M2 / M1`

.. history
.. authors
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