Don't try this at home without checking (read: delete) the first line.....and, if you feel brave, or you'd like to keep your customers, add something to the bottom..... >;) -Steve
While they should not be announcing, you should not be listening. Try this and call back in the morning if it does not work.
access-list 181 deny ip host 0.0.0.0 any access-list 181 deny ip 10.0.0.0 0.255.255.255 255.0.0.0 0.255.255.255 access-list 181 deny ip 127.0.0.0 0.255.255.255 255.0.0.0 0.255.255.255 access-list 181 deny ip 128.0.0.0 0.0.255.255 255.255.0.0 0.0.255.255 access-list 181 deny ip 172.16.0.0 0.15.255.255 255.240.0.0 0.15.255.255 access-list 181 deny ip 191.255.0.0 0.0.255.255 255.255.0.0 0.0.255.255 access-list 181 deny ip 192.0.2.0 0.0.0.255 255.255.255.0 0.0.0.255 access-list 181 deny ip 192.168.0.0 0.0.255.255 255.255.0.0 0.0.255.255 access-list 181 deny ip 192.0.0.0 0.0.0.255 255.255.255.0 0.0.0.255 access-list 181 deny ip 223.255.255.0 0.0.0.255 255.255.255.0 0.0.0.255