Hello experts,


I'm working in BGP home lab, I do want to clarify that the use of static NULL 0 route.


There is loopback interfaces in two iBGP domain in R1, in R2 and the network between two iBGP routers  is


When I advertise and into BGP, from the eBGP side can't find these networks by using show ip bgp 

But after I run ip route null 0 from iBGP side and advertise, I can find the in eBGP side.

Please explain me the use of NULL0 static route why it need ?


Thanks in advance,[:D]


  • peetypeety ✭✭✭

    Great job labbing this up so you can see things first-hand. When you say "I advertise and into BGP", how are you accomplishing this?

    My suspicion, without seeing your configs yet, is that you had a network statement for, and you were hoping your loopbacks and inter-router link would advertise because they're in that network. BGP is, for better and worse, very particular about its network statements, and they must be an exact match for the BGP route to be generated. You could also explore 'aggregate-address' to have the router create the /16 aggregate route if any longer route exists within it.

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