fix to add more fixes on top of previous pull request

docs/configuration/firewall/index.rst

@@ -4,26 +4,27 @@
 Firewall
 ########
 
-With VyOS being based on top of Linux and its kernel, the Netfilter project
+As VyOS is based on Linux it leverages its firewall. The Netfilter project
 created iptables and its successor nftables for the Linux kernel to
-work directly on the data flows. This now extends the concept of zone-based
+work directly on packet data flows. This now extends the concept of 
-security to allow for manipulating the data at multiple stages once accepted
+zone-based security to allow for manipulating the data at multiple stages once 
-by the network interface and the driver before being handed off to the
+accepted by the network interface and the driver before being handed off to 
-destination (e.g., a web server OR another device).
+the destination (e.g., a web server OR another device).
 
-A simplified traffic flow diagram, based on Netfilter packet flow, is shown next, in
+A simplified traffic flow diagram, based on Netfilter packet flow, is shown 
-order to have a full view and understanding of how packets are processed, and
+next, in order to have a full view and understanding of how packets are 
-what possible paths traffic can take.
+processed, and what possible paths traffic can take.
 
 .. figure:: /_static/images/firewall-gral-packet-flow.png
 
-Main points regarding this packet flow and terminology used in VyOS firewall are below:
+The main points regarding this packet flow and terminology used in VyOS 
+firewall are covered below:
 
-   * **Bridge Port?**: choose appropriate path based on whether interface where the
+   * **Bridge Port?**: choose appropriate path based on whether interface 
-     packet was received is part of a bridge, or not.
+     where the packet was received is part of a bridge, or not.
 
-If interface where the packet was received isn't part of a bridge, then packet
+If the interface where the packet was received isn't part of a bridge, then 
-is processed at the **IP Layer**:
+packetis processed at the **IP Layer**:
 
    * **Prerouting**: several actions can be done in this stage, and currently
      these actions are defined in different parts in VyOS configuration. Order
@@ -79,8 +80,8 @@ is processed at the **IP Layer**:
      * **Source NAT**: rules defined under ``set [nat | nat66]
        destination...``.
 
-If interface where the packet was received is part of a bridge, then packet
+If the interface where the packet was received is part of a bridge, then 
-is processed at the **Bridge Layer**, which contains a basic setup for
+packetis processed at the **Bridge Layer**, which contains a basic setup for
 bridge filtering:
 
    * **Forward (Bridge)**: stage where traffic that is trespasing through the
@@ -88,7 +89,7 @@ bridge filtering:
 
      * ``set firewall bridge forward filter ...``.
 
-Main structure VyOS firewall cli is shown next:
+The main structure VyOS firewall cli is shown next:
 
 .. code-block:: none
 
@@ -134,7 +135,7 @@ Main structure VyOS firewall cli is shown next:
             - custom_zone_name
                + ...
 
-Please, refer to appropiate section for more information about firewall
+Please, refer to appropriate section for more information about firewall
 configuration:
 
 .. toctree::

docs/configuration/firewall/index.rst~

@@ -0,0 +1,179 @@
+:lastproofread: 2023-11-23
+
+########
+Firewall
+########
+
+With VyOS being based on top of Linux and its kernel, the Netfilter project
+created iptables and its successor nftables for the Linux kernel to
+work directly on the data flows. This now extends the concept of zone-based
+security to allow for manipulating the data at multiple stages once accepted
+by the network interface and the driver before being handed off to the
+destination (e.g., a web server OR another device).
+
+A simplified traffic flow diagram, based on Netfilter packet flow, is shown next, in
+order to have a full view and understanding of how packets are processed, and
+what possible paths traffic can take.
+
+.. figure:: /_static/images/firewall-gral-packet-flow.png
+
+Main points regarding this packet flow and terminology used in VyOS firewall are below:
+
+   * **Bridge Port?**: choose appropriate path based on whether interface where the
+     packet was received is part of a bridge, or not.
+
+If interface where the packet was received isn't part of a bridge, then packet
+is processed at the **IP Layer**:
+
+   * **Prerouting**: several actions can be done in this stage, and currently
+     these actions are defined in different parts in VyOS configuration. Order
+     is important, and all these actions are performed before any actions
+     defined under ``firewall`` section. Relevant configuration that acts in
+     this stage are:
+
+      * **Conntrack Ignore**: rules defined under ``set system conntrack ignore
+        [ipv4 | ipv6] ...``.
+
+      * **Policy Route**: rules defined under ``set policy [route | route6]
+        ...``.
+
+      * **Destination NAT**: rules defined under ``set [nat | nat66]
+        destination...``.
+
+   * **Destination is the router?**: choose appropriate path based on
+     destination IP address. Transit forward continues to **forward**,
+     while traffic that destination IP address is configured on the router
+     continues to **input**.
+
+   * **Input**: stage where traffic destined for the router itself can be
+     filtered and controlled. This is where all rules for securing the router
+     should take place. This includes ipv4 and ipv6 filtering rules, defined
+     in:
+
+     * ``set firewall ipv4 input filter ...``.
+
+     * ``set firewall ipv6 input filter ...``.
+
+   * **Forward**: stage where transit traffic can be filtered and controlled.
+     This includes ipv4 and ipv6 filtering rules, defined in:
+
+     * ``set firewall ipv4 forward filter ...``.
+
+     * ``set firewall ipv6 forward filter ...``.
+
+   * **Output**: stage where traffic that originates from the router itself
+     can be filtered and controlled. Bear in mind that this traffic can be a
+     new connection originated by a internal process running on VyOS router,
+     such as NTP, or a response to traffic received externaly through
+     **inputt** (for example response to an ssh login attempt to the router).
+     This includes ipv4 and ipv6 filtering rules, defined in:
+
+     * ``set firewall ipv4 input filter ...``.
+
+     * ``set firewall ipv6 output filter ...``.
+
+   * **Postrouting**: as in **Prerouting**, several actions defined in
+     different parts of VyOS configuration are performed in this
+     stage. This includes:
+
+     * **Source NAT**: rules defined under ``set [nat | nat66]
+       destination...``.
+
+If interface where the packet was received is part of a bridge, then packet
+is processed at the **Bridge Layer**, which contains a basic setup for
+bridge filtering:
+
+   * **Forward (Bridge)**: stage where traffic that is trespasing through the
+     bridge is filtered and controlled:
+
+     * ``set firewall bridge forward filter ...``.
+
+Main structure VyOS firewall cli is shown next:
+
+.. code-block:: none
+
+   - set firewall
+       * bridge
+            - forward
+               + filter
+       * flowtable
+            - custom_flow_table
+               + ...
+       * global-options
+            + all-ping
+            + broadcast-ping
+            + ...
+       * group
+            - address-group
+            - ipv6-address-group
+            - network-group
+            - ipv6-network-group
+            - interface-group
+            - mac-group
+            - port-group
+            - domain-group
+       * ipv4
+            - forward
+               + filter
+            - input
+               + filter
+            - output
+               + filter
+            - name
+               + custom_name
+       * ipv6
+            - forward
+               + filter
+            - input
+               + filter
+            - output
+               + filter
+            - ipv6-name
+               + custom_name
+       * zone
+            - custom_zone_name
+               + ...
+
+Please, refer to appropiate section for more information about firewall
+configuration:
+
+.. toctree::
+   :maxdepth: 1
+   :includehidden:
+
+   global-options
+   groups
+   bridge
+   ipv4
+   ipv6
+   flowtables
+
+.. note:: **For more information**
+   of Netfilter hooks and Linux networking packet flows can be
+   found in `Netfilter-Hooks
+   <https://wiki.nftables.org/wiki-nftables/index.php/Netfilter_hooks>`_
+
+
+Zone-based firewall
+^^^^^^^^^^^^^^^^^^^
+.. toctree::
+   :maxdepth: 1
+   :includehidden:
+
+   zone
+
+With zone-based firewalls a new concept was implemented, in addtion to the
+standard in and out traffic flows, a local flow was added. This local was for
+traffic originating and destined to the router itself. Which means additional
+rules were required to secure the firewall itself from the network, in
+addition to the existing inbound and outbound rules from the traditional
+concept above.
+
+To configure VyOS with the
+:doc:`zone-based firewall configuration </configuration/firewall/zone>`
+
+As the example image below shows, the device now needs rules to allow/block
+traffic to or from the services running on the device that have open
+connections on that interface.
+
+.. figure:: /_static/images/firewall-zonebased.png