>But I need immediately response to let server reject/delay the request from others computer.
I see. Well, perhaps someone else can help with some API that allows a more immediate communication between computers. I can't help you here.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)