BGP advertising a default route
Default routes are used by routing devices to forward packets to destination networks that are not specifically defined in entries within the routing table.
There are a couple of ways to configure a router running BGP to advertise a default route to its BGP peers:
-
Configure a static route to the 0.0.0.0/0 network pointing to the null 0 interface by issuing the
ip route 0.0.0.0 0.0.0.0 null0
command. Then use thenetwork 0.0.0.0
command to inject the route into BGP. -
Configure a static route to the 0.0.0.0/0 network pointing to the null 0 interface by issuing the
ip route 0.0.0.0 0.0.0.0 null 0
command. Then, redistribute this static route into BGP using theredistribute static
command in conjunction with theneighbor X.X.X.X default-originate
command to the neighbor to which you want to share that default route.
Links:
https://networklessons.com/bgp/how-to-advertise-networks-in-bgp/