Implicit filter for Default EBGP Route Propagation Behavior without Policies

Junos OS introduced a new configuration option defaults ebgp no-policy at the existing edit protocols bgp hierarchy level. The configuration option separates the default policy for receive and advertise, into separate clauses (accept, reject, or reject-always) to allow the route propagation behavior of EBGP speakers to vary independently from its default behavior. Previously, the default behavior of BGP was to receive and advertise all routes. With the introduction of this feature, the default behavior still remains to accept all routes for both receive and advertise, but you also have an option to reject routes by default. With the reject configuration, you can reject routes of type IPv4 or IPv6 unicast for instance type virtual-router, vrf, non-forwarding, and primary. With the reject-always configuration, you can reject all routes from being received or getting advertised, irrespective of address family or instance type. By using this feature, you can control traffic in leaf autonomous systems (AS) and thereby, prevent them from having to accidentally function as transit autonomous systems. Note: The introduction of this implicit filter does not affect the existing deployments that rely on the default behavior. To enable this feature, use the following configuration at [edit protocols bgp] hierarchy level, set defaults ebgp no-policy receive (accept | reject | reject-always); advertise (accept | reject | reject-always);