and now attack over LAND
this is a kind of spoofed ddos like - overwhelm you and push you out - attack against windows machines
Windows XP appears to be vulnerable only if SP-2 is installed.
Windows 2003 is vulnerable.
On systems with multiple CPUs, only one CPU will be 'maxed out'. These systems remain responsive (but will be slower)
Hyperthreading systems (newer Pentium IVs) behave like dual CPU systems in that the total load reaches 50%.
source Internet Storm Center
please be sure to protect your firewalls against spoofing and turn off any service you don't need on your servers on the open