A Land Attack sends SYN packets with the same source and destination IP addresses and the same source and destination ports to a host computer. This makes it appear as if the host computer sent the packet to itself. This will cause a Windows PC to be very slow as it tries to respond to itself or to crash.
Try to trace it back to see where the packet came from (look at mac addresses or a sniffer or debug ip packets). Then you can stop it.
Hope it helps.
Steve
