As already said before, these aggressive countermeasures may harm innocent people, and might also warn them that you are aware of the attack. There are cases (example, honeypots) where you want to retrieve the most information from the attacker. And even when this is not the case, remember that accurate logs will make it much easier to spot the attacker. Just bear in mind that in several incidents, you may need the cooperation of other administrators, isp and etc. There are several ways of hiding yourself when commiting computer crime, and more important, several ways of blaming someone else. Be careful.
IDS seems to be what you want. :)
