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Null0 Interface in Juniper ?

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  • 1.  Null0 Interface in Juniper ?

    Posted 11-11-2008 10:14



    Is there any equivalent interface in Juniper for Cisco's Null0 ? or We need to acheive that functionality with policy only ?

  • 2.  RE: Null0 Interface in Juniper ?
    Best Answer

    Posted 11-11-2008 13:40


    If you want to install a route in routing table even you don't have a next-hop you can use discard keyword ,

    for example : 



    Router# set routing-options static route A.B.C.D/M discard 


    Best Regards


  • 3.  RE: Null0 Interface in Juniper ?

    Posted 09-19-2017 04:22



    I would like to restrict some routes going out of my ABR router. Is it possible ?


    For example,


    In area 0, I have 10 routes. And these ten routes are going into area 1 as LSA1 routes.


    So, on a router in Area 1, i will see all the 10 routes from area 0 as LSA1.


    Now, I want only 4 LSA's out of 10 LSA's to be seen in routers in area 1.


    How to achieve this. Do I need to add some configuration on the ABR router or router in area1.


    For now, i have only one router in area1. ABR is part of area0 and area1.


  • 4.  RE: Null0 Interface in Juniper ?

    Posted 09-19-2017 06:15
    Probably better to post this as its own thread, rather than adding to a years-old thread on an unrelated topic. Anyway, you have some incorrect information here. Type 1 LSAs don't go from area to area; this information gets summarised in Type 3 LSAs instead. You can use import and export filters on your ABR to control what information will get passed from area to area.

  • 5.  RE: Null0 Interface in Juniper ?

    Posted 09-20-2017 04:17

    I think the only way to control external routes flowing from the backbone into area 1 is to make area 1 a stub area and inject a default route in it. If the external routes were in area 1 then you could use the area-range restrict statement.

  • 6.  RE: Null0 Interface in Juniper ?

    Posted 11-11-2008 14:38

    To expand on that a little, there is also the equivalent discard interface that you can apply a filter to if you are interested in what is going to your null0/discard interface: 


    interfaces {

        dsc {

            unit 0 {

                family inet {

                    filter {

                        output discards-out;






    firewall {

        family inet {

            filter discards-out {

                term discard-all {

                    then {

                        count discarded;