about udp 80,8080,0

These days, most of ddos attack use udp port 80.8080.0 in our country and our network. Sometimes the traffic volume is up to 100gbps higher. So, we are considering to rate(bps) control about udp port 8,8080,0 in our ISP network. Although such a ports arp not be used commonly... I'm wondering about whether any of problems happen after do that. Is there anyone who have experiences controlling udp port 8,8080,0 ? rate-limiting or block! What does application use 8.8080,0 port for the proper purpose? [chk_receive.html?msgid=1265716670&uniqid=23455&sender=eversuede%40chol .com]