arrange: nat, PBR, policy

This commit is contained in:
rebortg 2020-11-29 21:32:45 +01:00
parent bfb3814cd1
commit e7f01e6efc
4 changed files with 74 additions and 65 deletions

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@ -4,6 +4,12 @@
NAT NAT
### ###
.. toctree::
:maxdepth: 1
:includehidden:
nptv6
:abbr:`NAT (Network Address Translation)` is a common method of :abbr:`NAT (Network Address Translation)` is a common method of
remapping one IP address space into another by modifying network address remapping one IP address space into another by modifying network address
information in the IP header of packets while they are in transit across information in the IP header of packets while they are in transit across

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@ -1,5 +1,72 @@
.. include:: ../_include/need_improvement.txt .. include:: ../_include/need_improvement.txt
######
Policy
######
Routing Policies could be used to tell the router (self or neighbors) what
routes and their attributes needs to be put into the routing table.
There could be a wide range of routing policies. Some examples are below:
* Set some metric to routes learned from a particular neighbor
* Set some attributes (like AS PATH or Community value) to advertised routes to neighbors
* Prefer a specific routing protocol routes over another routing protocol running on the same router
Example
=======
**Policy definition:**
.. code-block:: none
# Create policy
set policy route-map setmet rule 2 action 'permit'
set policy route-map setmet rule 2 set as-path-prepend '2 2 2'
# Apply policy to BGP
set protocols bgp 1 neighbor 203.0.113.2 address-family ipv4-unicast route-map import 'setmet'
set protocols bgp 1 neighbor 203.0.113.2 address-family ipv4-unicast soft-reconfiguration 'inbound'
Using 'soft-reconfiguration' we get the policy update without bouncing the
neighbor.
**Routes learned before routing policy applied:**
.. code-block:: none
vyos@vos1:~$ show ip bgp
BGP table version is 0, local router ID is 192.168.56.101
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, R Removed
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 198.51.100.3/32 203.0.113.2 1 0 2 i < Path
Total number of prefixes 1
**Routes learned after routing policy applied:**
.. code-block:: none
vyos@vos1:~$ sho ip b
BGP table version is 0, local router ID is 192.168.56.101
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, R Removed
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 198.51.100.3/32 203.0.113.2 1 0 2 2 2 2 i
Total number of prefixes 1
vyos@vos1:~$
You now see the longer AS path.
.. include:: ../_include/need_improvement.txt
.. _routing-pbr: .. _routing-pbr:
### ###
@ -135,3 +202,4 @@ Add multiple source IP in one rule with same priority
set policy local-route rule 101 source '192.0.1.254' set policy local-route rule 101 source '192.0.1.254'
set policy local-route rule 101 source '192.0.1.253' set policy local-route rule 101 source '192.0.1.253'
set policy local-route rule 101 source '203.0.113.0/24' set policy local-route rule 101 source '203.0.113.0/24'

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@ -1,65 +0,0 @@
.. include:: ../_include/need_improvement.txt
######
Policy
######
Routing Policies could be used to tell the router (self or neighbors) what
routes and their attributes needs to be put into the routing table.
There could be a wide range of routing policies. Some examples are below:
* Set some metric to routes learned from a particular neighbor
* Set some attributes (like AS PATH or Community value) to advertised routes to neighbors
* Prefer a specific routing protocol routes over another routing protocol running on the same router
Example
=======
**Policy definition:**
.. code-block:: none
# Create policy
set policy route-map setmet rule 2 action 'permit'
set policy route-map setmet rule 2 set as-path-prepend '2 2 2'
# Apply policy to BGP
set protocols bgp 1 neighbor 203.0.113.2 address-family ipv4-unicast route-map import 'setmet'
set protocols bgp 1 neighbor 203.0.113.2 address-family ipv4-unicast soft-reconfiguration 'inbound'
Using 'soft-reconfiguration' we get the policy update without bouncing the
neighbor.
**Routes learned before routing policy applied:**
.. code-block:: none
vyos@vos1:~$ show ip bgp
BGP table version is 0, local router ID is 192.168.56.101
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, R Removed
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 198.51.100.3/32 203.0.113.2 1 0 2 i < Path
Total number of prefixes 1
**Routes learned after routing policy applied:**
.. code-block:: none
vyos@vos1:~$ sho ip b
BGP table version is 0, local router ID is 192.168.56.101
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, R Removed
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 198.51.100.3/32 203.0.113.2 1 0 2 2 2 2 i
Total number of prefixes 1
vyos@vos1:~$
You now see the longer AS path.