Blocking broadcast of Default route via BGP

8 replies
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Hey,

This is my problem:

How do I block default route from being broadcast over BGP?

Thanks!

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Iescudero

New Member

Hello!!

First a Prefix:

config router prefix-list edit "Blocked Default Route" set comments "Bloquea aprendizaje de rutas por BGP de la MPLS" config rule edit 1 set prefix 192.168.0.0 255.255.0.0 next end

Then a Route Map:

config router route-map edit "ROUTE_MAP_DEFAULT" config rule edit 1 set action deny set match-ip-address "Blocked Default Route" next end

And last, apply Route Map in your neighbour:

config router bgp set as 64XXX config neighbor edit "XXX.XXX.XXX.XXX" set remote-as 64XXX set route-map-in "ROUTE_MAP_DEFAULT" end

Maybe exist a better solution, but this one worked for me when i dont want to learn some routes.

Hope it helps.

Iescudero

New Member

Ups i made a mistake:

This is the right prefix for you:

config router prefix-list edit "Blocked Default Route" config rule edit 1 set prefix 0.0.0.0 0.0.0.0 next end

Cyas

gilfalkoAuthor

New Member

This will block EVERYTHING, not just the default route,...

emnoc

New Member

try

In the mask "set prefix 0.0.0.0 255.255.255.255" or "set prefix 0.0.0.0/0"

Ken

gilfalkoAuthor

New Member

Well, I nailed it eventually :)

This was an ACCESS-LIST but there's a small "twist" sort of speak which is not mentioned in the Forti documents as usual.

config router access-list edit "Block_Def_Route" config rule edit 1 set action deny set exact-match enable next edit 2 set exact-match disable next end next end

config neighbor edit "10.40.15.1" set distribute-list-in "Block_Def_Route" set remote-as 6167 set route-map-out "Verizon_Prepend1" next edit "10.40.16.1" set distribute-list-in "Block_Def_Route" set remote-as 6167 set route-map-out "Verizon_Prepend" next end

Without adding the bolded text this would have never worked.

what it means is to allow everything else BUT what is being actioned as "denied"