Anyone approaching my porch should notice this sign:
If that didn't dissuade you, and you still want to get on my porch, you have to come through a latched metal gate. You basically have to put your hand on this notice to open the gate:
If you ignore the notice and unlatch the gate, and you aren't concerned about the eruption of dog-barking from within, this is posted on the screen door:
I don't know how to be more clear.