Different methods to advertise a default route in BGP Part 2:

Now let's go through the 2nd method to advertise a default route in BGP.

Method 2: Using default-originate command in the neighbor statement

I’ve removed the default static route from R1 which removes the default route on R2 and R3 dynamically.

 

We can achieve the advertisement of default route in BGP without configuring a static default route on a router (which means it doesn’t have a 0.0.0.0/0 via next hop entry on a router)

Command to achieve this:

 

Let’s look at the routing table of R1 first

 

There is no 0.0.0.0/0 entry as expected. Now let’s look at the routing table of R2 and R3 respectively

 

      The main difference between the first 2 methods:

            1)  Using network command: Static default route entry is required in the routing table of the router which is advertising 0.0.0.0/0 

           2)  Using default-originate in the neighbour statement: Static default route entry is not necessarily required in the routing table.

We will see the 3^rd method for advertising the default route in BGP in the next post.