Routing

 View Only

IMPORTANT MODERATION NOTICE

This community is currently under full moderation, meaning  all posts will be reviewed before appearing in the community. Please expect a brief delay—there is no need to post multiple times. If your post is rejected, you'll receive an email outlining the reason(s). We've implemented full moderation to control spam. Thank you for your patience and participation.



  • 1.  BGP Link-local Nexthop Error SRX

    Posted 07-27-2022 15:15
    Hello,

    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


    ------------------------------
    STEVE HOGEVEEN
    ------------------------------


  • 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)

    ------------------------------
    STEVE HOGEVEEN
    ------------------------------