how to block arp messages
 

My ethernet monitor shows internet activity permanently even when i'm not using it. I installed ethereal and discovered that 99% of this strange activity is due to arp messages. If possible, could anyone tell me if they are harmful? is it possible to block this kind of messages? If so, how can i do this. thanx in advance.

I wouldn't block ARP packets unless you want your network to stop working.
http://linux-ip.net/html/ether-arp.html