How to stay on the local network ?

Hello,

I am using KepeserverEx (PC A) to send data on a greengrass device (PC B). Both are in the same room.
I would like that the communication stay on the local network but it doesn't seem to be that way.

When I send the data to the topic/kepserver (with the right subscription and policy), I cannot send it to a local lambda function (greengrass).
Typically, I need to add the subscription IoT Cloud -> myLambda.
But it means the data goes through the network am I right ?
So I trie to add a device to my greengrass, and allow communication between the 2 of them, but same issue.

Also how is it possible that I see the data in the "test" section, without the subscription to my topic/kepserver ?
I never allowed the device on PC A to communication to the IoT Cloud on any topic (only in the pac A's device policy). Did I miss something ?

Any idea would be awesome,
Thank you, J

Edited by: jerome123210 on Mar 11, 2020 1:33 AM