IP 碎片攻击怎么防御?

[cloud2000]

主机商来信说，我的 vps 被 IP 碎片攻击。我印象中这不是早就 out 的攻击么？ log 类似如下:

2016-09-04 09:24:17 Fragmented traffic! From 112.97.61.131:23614 to xxx.xxx.xxx.xxx:443,

2016-09-04 09:24:17 Fragmented traffic! From 112.97.61.131:20203 to xxx.xxx.xxx.xxx:25041,

2016-09-04 09:24:22 Fragmented traffic! From 112.97.61.131:24435 to xxx.xxx.xxx.xxx:41458,

2016-09-04 09:24:22 Fragmented traffic! From 112.97.61.131:23614 to xxx.xxx.xxx.xxx:443,