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author | Nick Anderegg <nick@anderegg.io> | 2023-09-10 20:20:13 -0400 |
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committer | Nick Anderegg <nick@anderegg.io> | 2023-09-12 20:55:59 -0400 |
commit | 5a57f5968dc45df162f8643a2f575db39087fac9 (patch) | |
tree | 1a69757099493d253f4fb945d82114f715c668b4 | |
parent | 31f741269dc4a6b2afa6c6cf4ad2c3d746e4953c (diff) | |
download | vyos-documentation-5a57f5968dc45df162f8643a2f575db39087fac9.tar.gz vyos-documentation-5a57f5968dc45df162f8643a2f575db39087fac9.zip |
quick-start: add clarifying context to nftables config examples
-rw-r--r-- | docs/quick-start.rst | 110 |
1 files changed, 66 insertions, 44 deletions
diff --git a/docs/quick-start.rst b/docs/quick-start.rst index 2f428fe9..3a149c78 100644 --- a/docs/quick-start.rst +++ b/docs/quick-start.rst @@ -7,16 +7,16 @@ Quick Start This chapter will guide you on how to get up to speed quickly using your new VyOS system. It will show you a very basic configuration example that will provide a :ref:`nat` gateway for a device with two network interfaces -(`eth0` and `eth1`). +(``eth0`` and ``eth1``). .. _quick-start-configuration-mode: Configuration Mode ################## -By default, VyOS is in operational mode, and the command prompt displays a `$`. +By default, VyOS is in operational mode, and the command prompt displays a ``$``. To configure VyOS, you will need to enter configuration mode, resulting in the -command prompt displaying a `#`, as demonstrated below: +command prompt displaying a ``#``, as demonstrated below: .. code-block:: none @@ -43,10 +43,10 @@ the following command: Interface Configuration ####################### -* Your outside/WAN interface will be `eth0`. It will receive its interface +* Your outside/WAN interface will be ``eth0``. It will receive its interface address via DHCP. -* Your internal/LAN interface will be `eth1`. It will use a static IP address - of `192.168.0.1/24`. +* Your internal/LAN interface will be ``eth1``. It will use a static IP address + of ``192.168.0.1/24``. After switching to :ref:`quick-start-configuration-mode` issue the following commands: @@ -81,11 +81,11 @@ The following settings will configure DHCP and DNS services on your internal/LAN network, where VyOS will act as the default gateway and DNS server. -* The default gateway and DNS recursor address will be `192.168.0.1/24` -* The address range `192.168.0.2/24 - 192.168.0.8/24` will be reserved for +* The default gateway and DNS recursor address will be ``192.168.0.1/24`` +* The address range ``192.168.0.2/24 - 192.168.0.8/24`` will be reserved for static assignments * DHCP clients will be assigned IP addresses within the range of - `192.168.0.9 - 192.168.0.254` and have a domain name of `internal-network` + ``192.168.0.9 - 192.168.0.254`` and have a domain name of ``internal-network`` * DHCP leases will hold for one day (86400 seconds) * VyOS will serve as a full DNS recursor, replacing the need to utilize Google, Cloudflare, or other public DNS servers (which is good for privacy) @@ -121,13 +121,24 @@ network via IP masquerade. Firewall ######## -.. note:: Starting from VyOS 1.4-rolling-202308040557, a new firewall structure can be - found on all vyos instalations. Documentation for most of the new firewall CLI - can be found in the :ref:`firewall` chapter. The legacy firewall is still available - for versions before 1.4-rolling-202308040557 and can be found in the +A new firewall structure—which uses the ``nftables`` backend, rather +than ``iptables``—is available on all installations starting from +VyOS ``1.4-rolling-202308040557``. The firewall supports creation of distinct, +interlinked chains for each +`Netfilter hook <https://wiki.nftables.org/wiki-nftables/index.php/Netfilter_hooks>`_ +and allows for more granular control over the packet filtering process. + +.. note:: Documentation for most of the new firewall CLI + can be found in the :ref:`firewall` chapter.The legacy firewall is still available + for versions before ``1.4-rolling-202308040557`` and can be found in the :ref:`firewall-legacy` chapter. The examples in this section use the new configuration. +The firewall begins with the base ``filter`` tables you define for each of the +``forward``, ``input``, and ``output`` Netfiter hooks. Each of these tables is +populated with rules that are processed in order and can jump to other chains +for more granular filtering. + Configure Firewall Groups ------------------------- @@ -136,10 +147,10 @@ networks, addresses, ports, and domains that describe different parts of our network. We can then use them for filtering within our firewall rulesets, allowing for more concise and readable configuration. -In this case, we will create two interface groups—a `WAN` group for our -interfaces connected to the public internet and a `LAN` group for the interfaces +In this case, we will create two interface groups—a ``WAN`` group for our +interfaces connected to the public internet and a ``LAN`` group for the interfaces connected to our internal network. Additionally, we will create a network group, -`NET-INSIDE-v4`, that contains our internal subnet. +``NET-INSIDE-v4``, that contains our internal subnet. .. code-block:: none @@ -147,45 +158,56 @@ connected to our internal network. Additionally, we will create a network group, set firewall group interface-group LAN interface eth1 set firewall group network-group NET-INSIDE-v4 network '192.168.0.0/24' -Stateful Packet Filtering -------------------------- +Configure Stateful Packet Filtering +----------------------------------- + +With the new firewall structure, we have have a lot of flexibility in how we +group and order our rules, as shown by the two alternative approaches below. -Using the new firewall structure, we can create a common chain for stateful -connection filtering of multiple interfaces (or multiple netfilter hooks on one -interface). Those individual chains can then jump to the common chain for -stateful connection filtering, returning to the original chain for further -rule processing if no action is taken on the packet: +Option 1: Common Chain +^^^^^^^^^^^^^^^^^^^^^^ + +We can create a common chain for stateful connection filtering of multiple +interfaces (or multiple netfilter hooks on one interface). Those individual +chains can then jump to the common chain for stateful connection filtering, +returning to the original chain for further rule processing if no action is +taken on the packet. + +The chain we will create is called ``CONN_FILTER`` and has three rules: + +- A default action of ``return``, which returns the packet back to the original + chain is no action is taken. +- A rule to ``accept`` packets from established and related connections. +- A rule to ``drop`` packets from invalid connections. .. code-block:: none - # Create a new chain for stateful connection filtering that - # will return to the original chain if no action is taken set firewall ipv4 name CONN_FILTER default-action 'return' - # Allow established and related traffic set firewall ipv4 name CONN_FILTER rule 10 action 'accept' set firewall ipv4 name CONN_FILTER rule 10 state established 'enable' set firewall ipv4 name CONN_FILTER rule 10 state related 'enable' - # Drop invalid traffic set firewall ipv4 name CONN_FILTER rule 20 action 'drop' set firewall ipv4 name CONN_FILTER rule 20 state invalid 'enable' -Then, we can jump to the common chain from both the `forward` and `input` hooks +Then, we can jump to the common chain from both the ``forward`` and ``input`` hooks as the first filtering rule in the respective chains: .. code-block:: none - # Add a filter for the `forward` hook that sends all packets to CONN_FILTER set firewall ipv4 forward filter rule 10 action 'jump' set firewall ipv4 forward filter rule 10 jump-target CONN_FILTER - # Add a filter for the `input` hook that sends all packets to that same chain set firewall ipv4 input filter rule 10 action 'jump' set firewall ipv4 input filter rule 10 jump-target CONN_FILTER -Alternatively, you can take the more traditional approach of creating rules on -each hook's chain for stateful connection filtering: +Option 2: Per-Hook Chain +^^^^^^^^^^^^^^^^^^^^^^^^ + +Alternatively, instead of configuring the ``CONN_FILTER`` chain described above, +you can take the more traditional stateful connection filtering approach by +creating rules on each hook's chain: .. code-block:: none @@ -208,9 +230,9 @@ Now that we have configured stateful connection filtering to allow traffic from established and related connections, we can block all other incoming traffic addressed to our local network. -Create a new chain (`OUTSIDE-IN`) which will drop all traffic that is not +Create a new chain (``OUTSIDE-IN``) which will drop all traffic that is not explicity allowed at some point in the chain. Then, we can jump to that chain -from the `forward` hook when traffic is coming from the `WAN` interface group +from the ``forward`` hook when traffic is coming from the ``WAN`` interface group and is addressed to our local network. .. code-block:: none @@ -223,30 +245,30 @@ and is addressed to our local network. set firewall ipv4 forward filter rule 100 destination group network-group NET-INSIDE-v4 We should also block all traffic destinated to the router itself that isn't -explicitly allowed at some point in the chain for the `input` hook. As +explicitly allowed at some point in the chain for the ``input`` hook. As we've already configured stateful packet filtering above, we only need to -set the default action to `drop`: +set the default action to ``drop``: .. code-block:: none set firewall ipv4 input filter default-action 'drop' -Configure Management Access +Allow Management Access --------------------------- We can now configure access to the router itself, allowing SSH access from the inside/LAN network and rate limiting SSH access from the outside/WAN network. -First, create a new dedicated chain (`VyOS_MANAGEMENT`) for management +First, create a new dedicated chain (``VyOS_MANAGEMENT``) for management access, which returns to the parent chain if no action is taken. Add a rule -to accept traffic from the `LAN` interface group: +to accept traffic from the ``LAN`` interface group: .. code-block:: none set firewall ipv4 name VyOS_MANAGEMENT default-action 'return' -Configure a rule on the `input` hook filter to jump to the `VyOS_MANAGEMENT` +Configure a rule on the ``input`` hook filter to jump to the ``VyOS_MANAGEMENT`` chain when new connections are addressed to port 22 (SSH) on the router itself: .. code-block:: none @@ -256,8 +278,8 @@ chain when new connections are addressed to port 22 (SSH) on the router itself: set firewall ipv4 input filter rule 20 destination port 22 set firewall ipv4 input filter rule 20 protocol tcp -Finally, configure the `VyOS_MANAGEMENT` chain to accept connection from the -`LAN` interface group while limiting requests coming from the `WAN` interface +Finally, configure the ``VyOS_MANAGEMENT`` chain to accept connection from the +``LAN`` interface group while limiting requests coming from the ``WAN`` interface group to 4 per minute: .. code-block:: none @@ -287,7 +309,7 @@ all connections coming from localhost: set firewall ipv4 input filter rule 30 source address 127.0.0.0/8 Finally, we can allow access to the DNS recursor we configured earlier, -accepting traffic bound for port 53 from all hosts on the `NET-INSIDE-v4` +accepting traffic bound for port 53 from all hosts on the ``NET-INSIDE-v4`` network: .. code-block:: none @@ -314,7 +336,7 @@ Hardening Especially if you are allowing SSH remote access from the outside/WAN interface, there are a few additional configuration steps that should be taken. -Replace the default `vyos` system user: +Replace the default ``vyos`` system user: .. code-block:: none |