Creating a route filtering policy

In this section, you configure a route filtering policy on R2 using access lists to deny incoming routes from 10.0.20.0/24.

Table 1. Route filtering configuration
Router	Step	Command(s)
R2	Create an access list and a rule to deny specified routes.	`vyatta@R2# set policy access-list 100 rule 10 action deny`
R2	Match any destination.	`vyatta@R2# set policy access-list 100 rule 10 destination any`
R2	Match source 10.0.20.0.	`vyatta@R2# set policy access-list 100 rule 10 source network 10.0.20.0`
R2	Specify the inverse mask for the network.	`vyatta@R2# set policy access-list 100 rule 10 source inverse-mask 0.0.0.255`
R2	Create a rule to permit all other routes.	`vyatta@R2# set policy access-list 100 rule 20 action permit`
R2	Match any destination.	`vyatta@R2# set policy access-list 100 rule 20 destination any`
R2	Match any source.	`vyatta@R2# set policy access-list 100 rule 20 source any`
R2	Commit the changes.	`vyatta@R2# commit`
R2	Display the configuration.	`vyatta@R2# show policy access-list 100 { rule 10 { action deny destination { any } source { inverse-mask 0.0.0.255 network 10.0.20.0 } } rule 20 { action permit destination { any } source { any } } }`

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