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Announce your own prefixes

Purpose

As a network participating in the global Internet you want to tell other networks about your own prefixes and announce them to the public Internet.

Note

Your peers and upstreams might also apply incoming BGP filters to your BGP sessions and filter your prefixes. Please make sure to create appropriate RPKI objects, route/route6 objects and AS sets, for example in the RIPE datebase. It is best practice to also create an AS set although you currently only have one ASN, because if your BGP peers build filters based on your AS set you don't need to inform them if you ever announce prefixes with an additional origin ASN.

Configuration

Config snippet for JunOS


Please note that Cisco IOS is permissive by default. If you do not apply any filters, all prefixes will be shared between your BGP peers.

Config snippet for Cisco IOS


Config snippet for Cisco IOS XR


Config snippet for Arista EOS


Config snippet for FRRouting

ip prefix-list outgoing seq 10 permit 192.0.2.0/24
ip prefix-list outgoing seq 100 deny 0.0.0.0/0 le 32

ipv6 prefix-list outgoing-6 seq 10 permit 2001:db8::/32
ipv6 prefix-list outgoing-6 seq 100 deny ::/0 le 128

router bgp 64496
  no bgp default ipv4-unicast
  bgp log-neighbor-changes
  bgp router-id 192.0.2.10

  neighbor 198.51.100.1 remote-as 65550
  neighbor 3fff::1582 remote-as 65550

  address-family ipv4 unicast
    network 192.0.2.0/24
    neighbor 198.51.100.1 activate
    neighbor 198.51.100.1 prefix-list outgoing out
  exit-address-family

  address-family ipv6 unicast
    network 2001:db8::/32
    neighbor 3fff::1582 activate
    neighbor 3fff::1582 prefix-list outgoing-6 out
  exit-address-family
exit