Look down at the bottom of the Retaliation Page:

* Invasive Techniques - obtaining access privileges on the attacker's system, and then pursuing a strategy of disabling, destroying, or seizing control over the attacking assets.
* Symmetric Counterstrike - sending exploits and other attacks which are specific to vulnerabilities on the attacker's system, in an amount proportional to their current attacks.
* Asymmetric Counterstrike - preemptive measures in response to distributed attacks orchestrated by a known source. This retaliation could be far in excess of the attack that the aggressor has underway.
I know they have the OpenSims option. It's an interesting product that runs on OS X rack servers (which is different in of itself).