Router防火牆不明紀錄

各位大大，我的DIR-605L最近去看系統紀錄時，發現在21:00後

都有固定幾組IP被防火牆擋住，請問這是什麼情形？

浮動PPPoE應該不會那麼容易被鎖定該IP吧？

May 16 00:06:49 Per-source UDP Flood Attack Detect (ip=168.95.1.1) Packet Dropped
May 16 00:06:49 Per-source ACK Flood Attack Detect (ip=46.137.216.86) Packet Dropped
May 16 00:06:49 Whole System ACK Flood Attack from WAN Rule:Default deny
May 16 00:06:49 Whole System UDP Flood Attack from WAN Rule:Default deny
May 16 00:05:49 Per-source ACK Flood Attack Detect (ip=54.248.118.168) Packet Dropped
May 16 00:05:49 Whole System ACK Flood Attack from WAN Rule:Default deny
May 16 00:04:49 Per-source ACK Flood Attack Detect (ip=54.215.1.143) Packet Dropped
May 16 00:04:49 Whole System ACK Flood Attack from WAN Rule:Default deny
May 16 00:04:49 Whole System UDP Flood Attack from WAN Rule:Default deny
May 16 00:03:49 Per-source ACK Flood Attack Detect (ip=54.248.118.168) Packet Dropped

而46.137.216.86這組IP，用DNS查詢查到ec2-46-137-216-86.ap-southeast-1.compute.amazonaws.com



請問是什麼原因呢？