BGP Prefix List Filtering

Prefix list filtering allows filtering of routes on a specific neighbour basis by using a prefix list.

To create a prefix list, use the command ip prefix-list then apply it to a neighbour using the neighbour x.x.x.x prefix-list y followed by in or out. In will filter inbound, and out will filter outbound.

! Allow routes between 192.168.0.0 - 192.168.255.255 with a subnet mask of 255.255.255.0
ip prefix-list FILTER-IN seq 10 permit 192.168.0.0/16 ge 24

router bgp 65300
 address-family ipv4 unicast
 ! Filter inbound routes according to prefix list
 neighbor 10.0.0.1 prefix-list FILTER-IN in