Hi,
I found
this configuration example, which explains the VLAN settings either using the GUI or the CLI. Maybe this helps you solve your problem. Of course, the best source of wisdom is the
CLI reference guide (Chapter 75 starting at page 669).
I'm not sure what you mean, when you say "if i plug ... another device in the native VLAN". But anyway you obviously plugged two devices to ports with different VLAN settings. Could you show the port settings of these two ports, as shown in the CLI via "show vlan interface ethx/0/y"? Similarly, in case the three switches are not stacked, how are they interconnected to each other, and what do the port configurations (again "show vlan interface eth0/x") of the interconnection ports look like?
PT