network:nft-adv-block [RADIUSdesk]

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====== Firewall Profiles ======
===== Introduction =====
  * Firewall Profiles are the most advanced tool available in MESHdesk and APdesk to manage usage.
  * It allows you to tailor make a Firewall Profile and assign it to an Exit Point or selected user devices.
  * As an overview of available tools to mange usage we have:
        * **WiFi Schedules** -> Turns a specific SSID on and off on selected times.
        * **Throttling and Blocking Users** -> These are on selected user devices and always applied.
        * **Firewall Profiles** -> Swiss Knife that allows you to roll your own.
  * The rest of this document will cover Firewall Profiles in detail.

===== Design Philosophy =====
  * The design philosophy followed by most components in RADISUdesk is one of //define once, apply to many//.
  * With the Firewall Profiles we also follow this philosophy.
  * A Firewall Profile can be applied to user devices that connects to the MESHdesk and APdesk networks.
  * A Firewall Profile can also be applied to an Exit Point which is defined on a MESHdesk and APdesk network, e.g. a bridge, a NAT/DHCP gateway or a Captive Portal.
  * We also allow the root user to define site wide Firewall Profiles.
  * Site wide Firewall Profiles are available to **all** clouds.
  * This further reduces duplication.

===== Creating A Firewall Profile =====
  * The Firewall Profile Applet is available under **Other** -> **Firewall**
  * A Firewall Profile consists of the following:
        * Firewall Profile Name
        * One or more Rules
        * A Rule in turn can contain one or more Apps (If the Rule's category is selected as **App**)
  * Lets create a simple Firewall Profile that will block YouTube between 7AM and 5PM during weekdays.

==== Blocking YouTube During Week Days ====
  * Click on the Add Toolbar Button to create a new Firewall Profile
{{:network:nft-adv:firewall_profile1.png?nolink|}}
  * We selected to make it system wide (Indicated by the Umbrella Icon in the Name banner.)
{{:network:nft-adv:firewall_profile2.png?nolink|}}
  * Next we can start to add Rules.
  * If a rule's Category is App you should select one or more predefined Firewall Apps to be part of the rule.
  * An App has to be defined and contains a list of IP Addresses. (For the technical minded, these will be bundled into a **set** to be used by **nftables**.

==== Creating The YouTube Firewall App ====
  * To manage Firewall Apps, click on the toolbar button with the wrench (Tool-tip Firewall Apps)
  * This will open a new tab with a list of Firewall Apps.
{{:network:nft-adv:firewall_profile3.png?nolink|}}
  * Two items that need more explanation.
        * **FA Code**.  This is the Font Awesome code which will be translated to an easy to recognize Icon / Glyph.
        * Although it is cosmetic, it is also functional to identify Apps that's part of a rule.
        * You can consult this URL for available Icons: https://fontawesome.com/v4/cheatsheet/
        * **Elements**. These are IP addresses or ranges which will be used by nftables as part of their sets.
        * You can consult this URL to read up more on Sets and Elements inside Sets: https://wiki.nftables.org/wiki-nftables/index.php/Sets
  * Now we can return to our Firewall Profile to complete the new rule.

==== Rule for YouTube ====
  * The Add and Edit Rule form is very easy to use and also to make changes to existing rules.
{{:network:nft-adv:firewall_profile4.png?nolink|}}
  * You can combine as many rules as you like in one Firewall Profile.
  * Here we keep it simple by just blocking YouTube.

==== Using The Firewall Profile ====

  * Next we can associate it with an Exit Point on a MESH network or an AP Profile.
{{:network:nft-adv:firewall_profile5.png?nolink|}}
  * Alternatively you can associate it with a client's device.
{{:network:nft-adv:firewall_profile6.png?nolink|}}

===== Technical Details =====

  * If you are an old hand with Linux you are probably very familiar with **iptables**.
  * In the old days firewalls were done using **iptables** and in case you needed to do packet management on layer two you would use **ebtables**.
  * Fast forward to today and we have the much more advanced and user friendly **nftables**.
  * nftables allows you to do packet management on layer three and layer two.
  * OpenWrt version 22.03 migrated to use nftables instead of iptables.
  * This means that the feature will require OpenWrt version 22.03 or higher based firmware to work correct.
  * We took the opportunity to take advantage of this improvement and are using this with the Firewall Profile.
==== Using Available Meta Data ====
  * With nftables one can create filters based on //meta data//.
  * Meta data is data that is available but which are **not part of the traffic** flowing between two hosts on the Internet.
  * This includes detail about the hardware (e.g. the interface through which the traffic flows)
  * It also includes detail about the time when the traffic is flowing.
  * With these meta data filters that is available we formulated the options that you can select when adding a rule to a Firewall Profile.
  * One aspect which makes our implementation unique is the fact that we work on layer two and not layer three.
  * The reason for this is that MESHdesk and APdesk allows you to create bridged networks where the IP Address management (DHCP) can be done by another device on the network.
  * By working on layer two it allows us to formulate rules without the requirement to know the IP Address of a device or Exit Point to which the Firewall Profile is associated with.
  * You will need the compulsory **kmod-nft-bridge** nftable module.
  * Make sure it is included with the OpenWrt based firmware.
  * The **adv_meshdesk** bridge table is where things are happening.
  * You can inspect the table using the following command **nft -e -a list table bridge adv_meshdesk**.
<code javascript>
nft -e -a list table bridge adv_meshdesk
table bridge adv_meshdesk { # handle 2
        set YouTube { # handle 4
                type ipv4_addr
                flags interval
                elements = { 172.217.0.0/16 comment "Block YouTube" }
        }

        set md_lan { # handle 5
                type ipv4_addr
                flags interval
                elements = { 10.0.0.0/8, 172.16.0.0/12,
                             192.168.0.0/16 comment "Private IP Addr LAN" }
        }

        set md_internet_not { # handle 6
                type ipv4_addr
                flags interval
                elements = { 10.0.0.0/8, 172.16.0.0/12,
                             192.168.0.0/16 comment "Private IP Addr Excl For Internet" }
        }

        chain forward { # handle 1
                type filter hook forward priority 0; policy accept;
                meta day { "Monday", "Tuesday", "Wednesday", "Thursday", "Friday" } meta hour "07:00"-"17:00" iif "zero0" ip daddr @YouTube counter packets 0 bytes 0 drop comment "DROP ON zero0," # handle 8
        }

        chain input { # handle 2
                type filter hook input priority 0; policy accept;
                meta day { "Monday", "Tuesday", "Wednesday", "Thursday", "Friday" } meta hour "07:00"-"17:00" iif { "one0", "two1" } ip daddr @YouTube counter packets 0 bytes 0 drop comment "DROP ON two1,one0," # handle 11
        }

        chain output { # handle 3
                type filter hook output priority 0; policy accept;
        }
}
</code>
  * Here you can see the rules which were generated for the Youtube Block Firewall Profile which we defined and applied on a NAT/DHCP and also a bridged exit point.
  * The forward chain rule is for the bridged exit point.
  * The input chain rule is for the NAT/DHCP exit point.
  * As you can see our time of day and also the days to apply is in the meta day and meta hour parts respectively.