Difference between loopback and dummy interfaces for use in Linux routing

[Wilhelm Schuster]

On 2018-04-27 17:48, Grant Taylor wrote:
> On 04/27/2018 02:52 AM, Wilhelm Schuster wrote:
>> Hi,
> 
> Hi,

Thank you for the explanation.
>> What I’m struggling with is understanding the differences between both
>> interface types (besides the obvious difference in packet processing)
>> and when to use which.
> 
> My understanding is that it's not possible to add additional loopback
> interfaces on Linux.  Instead dummy interfaces are added and removed on
> Linux like loopbacks are added and removed on other NOSs.  (I know that
> you can create and remove loopback interfaces at whim on classic Cisco
> IOS.)

Can you give a scenario where I would want to use multiple dummy's
instead of just adding/removing addresses to the loopback interface? I
can't use a dummy interface for "real" packet processing since it just
drops the packet. If the use case is to make addresses from
loopback/dummy available on other interfaces, then does it matter if
those addresses originally came from a single lo or multiple dummy's?

Cheers, Wilhelm.