You need to control SSH, HTTP, and Telnet access to an MX240 router through any interface. You have decided to use a firewall filter. How should you apply the firewall filter?
A.
as an outbound filter on interface fxp0
B.
as an outbound filter on interface lo0
C.
as an inbound filter on interface fxp0
D.
as an inbound filter on interface lo0
A bit confusing but:
When you want to control access to the router, you’d normally need to apply those restrictions to every interface as the router can be contacted through any interface. However, to make things easier, Junos OS allows you to apply firewall filters to the loopback (lo0) interface.
Firewall filters applied to the lo0 interface affect all traffic destined to the router’s control plane, regardless of the interface on which the packet arrived. So to limit SSH and Telnet access to the router, you apply the filter to the lo0 interface.
in junos, all exception traffic pass thru lo0 interface. D is correct.