See a lot of net friend of post, in the use of kali Linux arospoof function of ARP deception

The echo 1 & gt; The/proc/sys/net/ipv4/ip_forward set forward, and the cat command to verify parameter Settings success

Type in arpspoof commands, but a target machine still is in offline state, what are the possible reasons of this kind of circumstance, the net friend give advice has been tried, or not, whether the data forwarding needs some conditions, such as the number and type of card, such as bosses, please comment!!!!!!