I am a bit confused at loopback interfaces and internal links interfaces..
As Junos JNCIA study guide mentions
"Management interfaces: Used to connect the device running the Junos OS to a management network. The actual
designation for this interface is platform-specific; examples include fxp0 and me0."
"Internal interfaces: Used to connect the control and forwarding planes. The actual designation for this interface is
platform-specific; examples include fxp1 and em0."
"Use the lo0 interface in conjunction with
routing protocols to facilitate routing in a redundant environment that is independent of the individual physical
links within that environment."
Very well, so fxp1 and em0 are the ports for internal link between RE and PFE, Why is it then in the same study guide when we want to filter traffic destined to the router itself like telnet/ssh/http we will use lo0? Shouldn't we use either fxp1 or em0 since its the link between RE and em0?
And is lo0 a routed port?
Why can't we just use the ingress interface as the destination ip address for telnet traffic or ssh traffic instead of using lo0 or fxp0?
I'm sorry for the confusion but I just want clarification on real-life applications for when to use each, fxp0 em0 lo0 and which is routed and which isnt?
Thanks in advance