Hi, I use ibgp to transport full tables in my network. iBGP delete my ASN but I use my ASN to identify my prefixes. So I added this code to my ibgp import filter if bgp_path ~ [= =] then { #bgp_path.prepend(LOCAL_ASN); if my_opt_prefix() then bgp_path.prepend(LOCAL_ASN); } It works when 2 servers connect, but when I have 3 servers, the third server can not import my first server's prefixed with my ASN. At the first server bird> show route export HOME_1_ARCH Table master6: 2a0c:e640:1017::/48 unreachable [BGP_Prefix 22:12:23.507] * (200) 2602:feda:ab9::/48 unreachable [BGP_Prefix 22:12:23.507] * (200) At the second server bird> show route for 2a0c:e640:1017:: export Aperture_IX all Table master6: 2a0c:e640:1017::/48 unicast [ZHYZ_PC 14:53:29.056] * (100) [AS141011i] via 2a0c:e640:1017::1 on zhyz_pc Type: BGP univ BGP.origin: IGP BGP.as_path: 141011 BGP.next_hop: 2a0c:e640:1017::1 BGP.local_pref: 100 At the third server bird> show route for 2a0c:e640:1017::/48 protocol HOME_1_ARCH all Table master6: ::/0 unicast [HOME_1_ARCH 06:10:14.802] * (100) [AS134835i] via 2602:feda:ab5::1 on home_1_arch Type: BGP univ BGP.origin: IGP BGP.as_path: 134835 BGP.next_hop: 2602:feda:ab5::1 BGP.local_pref: 100 BGP.community: (65530,2000) HOME_1_ARCH BGP --- up 06:10:14.802 Established Description: HOME_1_ARCH BGP BGP state: Established Neighbor address: 2602:feda:ab5::1%home_1_arch Neighbor AS: 141011 Local AS: 141011 Neighbor ID: 192.168.117.52 Local capabilities Multiprotocol AF announced: ipv6 Route refresh Graceful restart Restart time: 120 AF supported: ipv6 AF preserved: 4-octet AS numbers Enhanced refresh Long-lived graceful restart Neighbor capabilities Multiprotocol AF announced: ipv6 Route refresh Graceful restart Restart time: 120 AF supported: ipv6 AF preserved: 4-octet AS numbers Enhanced refresh Long-lived graceful restart Session: internal route-reflector AS4 Source address: 2602:feda:ab7::1 Hold timer: 183.267/240 Keepalive timer: 63.087/80 Channel ipv6 State: UP Table: master6 Preference: 100 Input filter: (unnamed) Output filter: (unnamed) Routes: 2560 imported, 129220 exported, 2557 preferred Route change stats: received rejected filtered ignored accepted Import updates: 266057 0 0 5170 260887 Import withdraws: 261009 0 --- 5382 255627 Export updates: 681596 17838 129330 --- 534428 Export withdraws: 3020 --- --- --- 131521 BGP Next hop: 2602:feda:ab7::1 You could see the third server cannot import 2a0c:e640:1017::/48 But when I deleted this code on the second server. if bgp_path ~ [= =] then { #bgp_path.prepend(LOCAL_ASN); if my_opt_prefix() then bgp_path.prepend(LOCAL_ASN); } it has been successful import bird> show route for 2a0c:e640:1017::/48 protocol HOME_1_ARCH all Table master6: 2a0c:e640:1017::/48 unicast [HOME_1_ARCH 07:14:07.526] * (100) [AS141011i] via 2602:feda:ab5::1 on home_1_arch Type: BGP univ BGP.origin: IGP BGP.as_path: 141011 BGP.next_hop: 2602:feda:ab5::1 BGP.local_pref: 100 BGP.originator_id: 172.16.229.1 BGP.cluster_list: 192.168.117.52 I know that maybe no one will use ibgp like this, but why it won't work?