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  • 1.  BGP Link-local Nexthop Error SRX

    Posted 07-27-2022 15:15

    I am hoping someone here can shed some light on an issue I am running into.

    I am trying to set up IPv6 BGP peering between a Juniper and one of our devices using the link-local addresses. The TCP sessions starts but it looks like the Juniper is sending its own link-local address twice for the nexthop as opposed to the interface global address and then the link-local.

    I would like to know if this is a bug or if this is a parameter that can be changed. I have updated the software to :
    Hostname: 300_J_L11_Atlas_R4
    Model: srx300
    Junos: 19.4R3.11 JUNOS
    Software Release [19.4R3.11]

    Here is what I am seeing in the packet capture the next hop should not have the link-local twice:
    20:08:40.082899 Out IP6 (class 0xc0, flowlabel 0xb72c1, hlim 1, next-header: TCP (6), length: 1314) fe80::cee1:9400:3c56:7530.bgp > fe80::164e:2aff:fe80:9265.52530: P 102:1384(1282) ack 627 win 15832 <nop,nop,timestamp 148026280 112787143>: BGP, length: 1282 Update Message (2), length: 103 Origin (1), length: 1, Flags [T]: IGP AS Path (2), length: 10, Flags [T]: 200 4000000100 Multi-Protocol Reach NLRI (14), length: 59, Flags [OE]: AFI: IPv6 (2), SAFI: Unicast (1) nexthop: fe80::cee1:9400:3c56:7530fe80::cee1:9400:3c56:7530, nh-length: 32, no SNPA


  • 2.  RE: BGP Link-local Nexthop Error SRX

    This message was posted by a user wishing to remain anonymous
    Posted 07-28-2022 12:28
    This message was posted by a user wishing to remain anonymous

    Hi Steve,

    Have you specified the local-interface under your bgp neighbour config?

  • 3.  RE: BGP Link-local Nexthop Error SRX

    Posted 07-29-2022 10:01
    Here is my config for the BGP SRX router:
    protocols {
    bgp {
    group Link_local {
    type external;
    local-interface irb.60;
    peer-as 4199999999;
    local-as 200;
    neighbor fe80::164e:2aff:fe80:9265;

    irb {
    unit 60 {
    family inet6 {
    address 2000:f26f:60::2021/127;

    admin@300_J_R4# run show interfaces irb.60
    Logical interface irb.60 (Index 70) (SNMP ifIndex 535)
    Flags: Up SNMP-Traps 0x0 Encapsulation: ENET2
    Bandwidth: 1Gbps
    Routing Instance: default-switch Bridging Domain: V60
    Input packets : 769887
    Output packets: 209350
    Destination: 2000:f28f:60::2020/127, Local: 2000:f28f:60::2020
    Addresses, Flags: Is-Preferred
    Destination: fe80::/64, Local: fe80::cee1:9400:3c56:7530

    This is the nexthop information the neighbour device is sending:
    nexthop: 2000:f26f::2020fe80::164e:2aff:fe80:9265, nh-length: 32, no SNPA

    This is the information the SRX is sending out:
    nexthop: fe80::cee1:9400:3c56:7530fe80::cee1:9400:3c56:7530, nh-length: 32, no SNPA

    Here is the error message the other device is sending back:
    Notification Message (3), length: 84, UPDATE Message Error (3), subcode Invalid NEXT_HOP Attribute (8)