家里的路由器遇到到端口扫描怎么办？

家里用的ADSL，然后通过路由器连接了几台主机。最近发现上网非常慢，打开网页都经常超时。于是用traceroute发现，各主机到家里的路由的时延都特别高，好不容易登录到路由上看日志，发现有大量的端口扫描日志，怀疑是路由忙于应付端口扫描而导致运行缓慢。已经开启了路由的防火墙(见下图)，不过似乎没有作用（超时仍然很严重），请问各位有什么办法么？

顺祝各位元旦快乐啊！！

防火墙的选项

路由器日志片段

241 Wed Jan 02 09:25:35 2013 [FW]Detected Port Scan from 213.109.90.228, drop it
242 Wed Jan 02 09:25:36 2013 [FW]Detected Port Scan from 31.130.126.101, drop it
243 Wed Jan 02 09:25:39 2013 [FW]Detected Port Scan from 62.122.102.102, drop it
244 Wed Jan 02 09:25:40 2013 [FW]Detected Port Scan from 176.116.213.106, drop it
245 Wed Jan 02 09:25:42 2013 [FW]Detected Port Scan from 92.124.93.104, drop it
246 Wed Jan 02 09:25:46 2013 [FW]Detected Port Scan from 77.121.59.155, drop it
247 Wed Jan 02 09:25:47 2013 [FW]Detected Port Scan from 197.251.141.170, drop it
248 Wed Jan 02 09:25:49 2013 [FW]Detected Port Scan from 187.13.201.183, drop it
249 Wed Jan 02 09:25:51 2013 [FW]Detected Port Scan from 83.152.84.199, drop it
250 Wed Jan 02 09:25:51 2013 [FW]Detected Port Scan from 78.101.87.146, drop it
251 Wed Jan 02 09:25:51 2013 [FW]Detected Port Scan from 173.169.18.200, drop it
252 Wed Jan 02 09:25:55 2013 [FW]Detected Port Scan from 177.73.35.211, drop it
253 Wed Jan 02 09:25:59 2013 [FW]Detected Port Scan from 178.216.16.180, drop it
254 Wed Jan 02 09:26:00 2013 [FW]Detected Port Scan from 109.107.80.138, drop it
255 Wed Jan 02 09:26:02 2013 [FW]Detected Port Scan from 87.231.225.130, drop it
256 Wed Jan 02 09:26:04 2013 [FW]Detected Port Scan from 85.29.64.33, drop it
257 Wed Jan 02 09:26:05 2013 [FW]Detected Port Scan from 181.29.152.90, drop it
258 Wed Jan 02 09:26:05 2013 [FW]Detected Port Scan from 83.82.1.40, drop it