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208 lines
6.4 KiB
ReStructuredText
208 lines
6.4 KiB
ReStructuredText
.. include:: /_include/need_improvement.txt
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######
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Policy
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######
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Routing Policies could be used to tell the router (self or neighbors) what
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routes and their attributes needs to be put into the routing table.
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There could be a wide range of routing policies. Some examples are below:
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* Set some metric to routes learned from a particular neighbor
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* Set some attributes (like AS PATH or Community value) to advertised routes
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to neighbors
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* Prefer a specific routing protocol routes over another routing protocol
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running on the same router
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Example
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=======
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**Policy definition:**
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.. code-block:: none
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# Create policy
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set policy route-map setmet rule 2 action 'permit'
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set policy route-map setmet rule 2 set as-path-prepend '2 2 2'
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# Apply policy to BGP
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set protocols bgp 1 neighbor 203.0.113.2 address-family ipv4-unicast route-map import 'setmet'
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set protocols bgp 1 neighbor 203.0.113.2 address-family ipv4-unicast soft-reconfiguration 'inbound'
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Using 'soft-reconfiguration' we get the policy update without bouncing the
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neighbor.
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**Routes learned before routing policy applied:**
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.. code-block:: none
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vyos@vos1:~$ show ip bgp
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BGP table version is 0, local router ID is 192.168.56.101
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Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
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r RIB-failure, S Stale, R Removed
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Origin codes: i - IGP, e - EGP, ? - incomplete
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Network Next Hop Metric LocPrf Weight Path
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*> 198.51.100.3/32 203.0.113.2 1 0 2 i < Path
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Total number of prefixes 1
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**Routes learned after routing policy applied:**
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.. code-block:: none
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vyos@vos1:~$ sho ip b
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BGP table version is 0, local router ID is 192.168.56.101
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Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
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r RIB-failure, S Stale, R Removed
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Origin codes: i - IGP, e - EGP, ? - incomplete
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Network Next Hop Metric LocPrf Weight Path
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*> 198.51.100.3/32 203.0.113.2 1 0 2 2 2 2 i
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Total number of prefixes 1
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vyos@vos1:~$
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You now see the longer AS path.
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.. _routing-pbr:
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###
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PBR
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###
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:abbr:`PBR (Policy-Based Routing)` allowing traffic to be assigned to
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different routing tables. Traffic can be matched using standard 5-tuple
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matching (source address, destination address, protocol, source port,
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destination port).
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Transparent Proxy
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=================
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The following example will show how VyOS can be used to redirect web
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traffic to an external transparent proxy:
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.. code-block:: none
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set policy route FILTER-WEB rule 1000 destination port 80
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set policy route FILTER-WEB rule 1000 protocol tcp
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set policy route FILTER-WEB rule 1000 set table 100
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This creates a route policy called FILTER-WEB with one rule to set the
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routing table for matching traffic (TCP port 80) to table ID 100
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instead of the default routing table.
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To create routing table 100 and add a new default gateway to be used by
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traffic matching our route policy:
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.. code-block:: none
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set protocols static table 100 route 0.0.0.0/0 next-hop 10.255.0.2
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This can be confirmed using the ``show ip route table 100`` operational
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command.
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Finally, to apply the policy route to ingress traffic on our LAN
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interface, we use:
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.. code-block:: none
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set interfaces ethernet eth1 policy route FILTER-WEB
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Multiple Uplinks
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================
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VyOS Policy-Based Routing (PBR) works by matching source IP address
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ranges and forwarding the traffic using different routing tables.
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Routing tables that will be used in this example are:
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* ``table 10`` Routing table used for VLAN 10 (192.168.188.0/24)
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* ``table 11`` Routing table used for VLAN 11 (192.168.189.0/24)
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* ``main`` Routing table used by VyOS and other interfaces not
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participating in PBR
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.. figure:: /_static/images/pbr_example_1.png
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:scale: 80 %
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:alt: PBR multiple uplinks
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Policy-Based Routing with multiple ISP uplinks
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(source ./draw.io/pbr_example_1.drawio)
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Add default routes for routing ``table 10`` and ``table 11``
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.. code-block:: none
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set protocols static table 10 route 0.0.0.0/0 next-hop 192.0.2.1
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set protocols static table 11 route 0.0.0.0/0 next-hop 192.0.2.2
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Add policy route matching VLAN source addresses
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.. code-block:: none
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set policy route PBR rule 20 set table '10'
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set policy route PBR rule 20 description 'Route VLAN10 traffic to table 10'
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set policy route PBR rule 20 source address '192.168.188.0/24'
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set policy route PBR rule 30 set table '11'
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set policy route PBR rule 30 description 'Route VLAN11 traffic to table 11'
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set policy route PBR rule 30 source address '192.168.189.0/24'
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Apply routing policy to **inbound** direction of out VLAN interfaces
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.. code-block:: none
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set interfaces ethernet eth0 vif 10 policy route 'PBR'
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set interfaces ethernet eth0 vif 11 policy route 'PBR'
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**OPTIONAL:** Exclude Inter-VLAN traffic (between VLAN10 and VLAN11)
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from PBR
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.. code-block:: none
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set policy route PBR rule 10 description 'VLAN10 <-> VLAN11 shortcut'
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set policy route PBR rule 10 destination address '192.168.188.0/24'
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set policy route PBR rule 10 destination address '192.168.189.0/24'
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set policy route PBR rule 10 set table 'main'
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These commands allow the VLAN10 and VLAN20 hosts to communicate with
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each other using the main routing table.
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Local route
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===========
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The following example allows VyOS to use :abbr:`PBR (Policy-Based Routing)`
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for traffic, which originated from the router itself. That solution for multiple
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ISP's and VyOS router will respond from the same interface that the packet was
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received. Also, it used, if we want that one VPN tunnel to be through one
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provider, and the second through another.
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* ``203.0.113.0.254`` IP addreess on VyOS eth1 from ISP1
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* ``192.168.2.254`` IP addreess on VyOS eth2 from ISP2
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* ``table 10`` Routing table used for ISP1
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* ``table 11`` Routing table used for ISP2
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.. code-block:: none
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set policy local-route rule 101 set table '10'
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set policy local-route rule 101 source '203.0.113.0.254'
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set policy local-route rule 102 set table '11'
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set policy local-route rule 102 source '192.0.2.254'
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set protocols static table 10 route '0.0.0.0/0' next-hop '203.0.113.0.1'
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set protocols static table 11 route '0.0.0.0/0' next-hop '192.0.2.2'
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Add multiple source IP in one rule with same priority
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.. code-block:: none
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set policy local-route rule 101 set table '10'
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set policy local-route rule 101 source '203.0.113.0.254'
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set policy local-route rule 101 source '203.0.113.0.253'
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set policy local-route rule 101 source '198.51.100.0/24'
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