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IRB interface Problem

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  • 1.  IRB interface Problem

    Posted 05-13-2011 17:40

    Hi All,


    I configure IRB interface on a routing instance,,, after that I checked the routing table of the routing instance so I found a route to IRB's ip address with a reject state??? 



    noc@MX960# show routing-instances NOC 
    instance-type virtual-router;
    interface irb.161;




    noc@MX960# show interfaces irb.161 

    family inet {







    noc@MX960# run show route table NOC.inet.0 


    NOC.inet.0: 8 destinations, 8 routes (8 active, 0 holddown, 0 hidden)

    + = Active Route, - = Last Active, * = Both

    *[Local/0] 01:04:00




    the output of the routing table must be indicating that the next-hop via irb.161 which is local, so what is the problem??/

  • 2.  RE: IRB interface Problem

    Posted 05-13-2011 19:44

    It seems that your bridge-domain is not functional ie your irb interface has hardware-down flag set.

    Could you please post the "show interfaces irb"?

    Check if interfaces bounded to bridge-domains are UP.

  • 3.  RE: IRB interface Problem

    Posted 05-14-2011 00:01

    Thanks alot man for your help...

    this is a simple of show commands that can help us:



    noc@MX960> show interfaces irb.161 terse                  
    Interface               Admin Link Proto    Local                 Remote
    irb.161                 up    down inet


    noc@MX960> show interfaces irb.161 terse                  Interface               Admin   Link         Proto    Local                 Remoteirb.161                                                                                                      up         down       inet                                                                                                                                                                  multiservice



    noc@MX960> show interfaces irb.161 extensive               

      Logical interface irb.161 (Index 248) (SNMP ifIndex 747) (Generation 451)

        Description: TO: default gateway NOC

        Flags: Hardware-Down SNMP-Traps 0x4004000 Encapsulation: ENET2

        Bandwidth: 1000mbps

        Routing Instance: default-switch Bridging Domain: VLAN_161+161

        Traffic statistics:

         Input  bytes  :                    0

         Output bytes  :                    0

         Input  packets:                    0

         Output packets:                    0

        Local statistics:

         Input  bytes  :                    0

         Output bytes  :                    0

         Input  packets:                    0

         Output packets:                    0

        Transit statistics:

         Input  bytes  :                    0                    0 bps

         Output bytes  :                    0                    0 bps

         Input  packets:                    0                    0 pps

         Output packets:                    0                    0 pps

        Protocol inet, MTU: 1514, Generation: 553, Route table: 17

          Flags: Sendbcast-pkt-to-re, Is-Primary

          Addresses, Flags: Dest-route-down Is-Default Is-Preferred Is-Primary

            Destination: 172.17.161/24, Local:, Broadcast:, Generation: 318

        Protocol multiservice, MTU: 1514, Generation: 554, Route table: 17

          Policer: Input: __default_arp_policer_


  • 4.  RE: IRB interface Problem
    Best Answer

    Posted 05-14-2011 02:24

    OK, than this means that you don't have any active(UP state) logical interfaces assigned to bridge-domain.

    In this case the "Reject" statement as next-hop means that for traffic who's destination is this IP address, router will generate "icmp unreachable".


  • 5.  RE: IRB interface Problem

    Posted 05-14-2011 22:29

    ohhh..... thats great...


    thanks alot bro....thanks man

  • 6.  RE: IRB interface Problem

    Posted 06-12-2017 14:45

    How did you resolve this? I have the same problem! Thanks in advance 🙂

  • 7.  RE: IRB interface Problem

    Posted 06-13-2017 03:04

    One of the physical sub interfaces you have assigned to the IRB group has to be link up.  If they are all link down the IRB will be link down.

  • 8.  RE: IRB interface Problem

    Posted 06-13-2017 05:36

    yes i resolved this

    1. upgrade your juniper the lasted version
    2. the subnet of the IRB interface can be recheable by the interface if not
    the interface gone a be down
    3. assign a interface IRB to a VLAN

    i hope this helps

    Johnattan Perez
    Ingeniero de Soporte
    Conian Technology
    Ofic.809-740-8080 Ext.4229,2262

  • 9.  RE: IRB interface Problem

    Posted 06-14-2017 00:10

    Hi Folks,

    There is a KB documenting the same,



  • 10.  RE: IRB interface Problem

    Posted 10-01-2016 17:11

    hi, do you can explain to me this i have the same problem