All connected Internet networks receive this traffic; it's collectively known as 'background noise' or 'backscatter' and there has been a considerable amount of scientific research done on it and what its origin and significance is. If you'd like to know more about it, take a look at the Wikipedia entry http://en.wikipedia.org/wiki/Internet_background_noise and the references mentioned there. Generally, there isn't anything you can do about it except firewall it out. The background noise is one of the reasons why amprgw only lets traffic through for hosts registered in the AMPR.ORG DNS. People with directly-connected subnets will have to deal with it on their own; background noise is one of the facts of Internet life. - Brian