ipfw中pipe的怪异现象

结构：

    ipfw做nat和pipe，em0接外网，em1接内网。

规则：

    在内网网卡em1上做的pipe

    在外网网卡em0上做nat

现象：

    在em0上做deny udp log规则，发现大量内网对外网的数据包。

    但用tcpdump，则抓不到这些udp包

    在外网网卡前接了一台交换机做端口镜像，也未发现这些udp包。

总结：

    ipfw有bug，本人英文不好，只等有人提交。

实例：

00500 1427266 1507125876 pipe 10 ip from any to 172.16.0.0/16 out via em1
00600 991873 307167807 pipe 20 ip from 172.16.0.0/16 to any in via em1

00931 0 0 deny log logamount 200 udp from any not 53,161 to any not dst-port 53,161 in via em1
00932 0 0 deny log logamount 200 udp from any not 53,161 to any not dst-port 53,161 out via em1

00940 6466 490695 deny log logamount 2000 udp from any not 53,161 to any not dst-port 53,161 in via em0
00941 20803 2562337 deny log logamount 2000 udp from any not 53,161 to any not dst-port 53,161 out via em0

00945 0 0 deny udp from any not 53,161 to any not dst-port 53,161 via em0
00950 0 0 deny udp from any not 53,161 to any not dst-port 53,161

00961 0 0 deny log logamount 200 udp from any not 53,161 to any not dst-port 53,161 in via em1
00962 0 0 deny log logamount 200 udp from any not 53,161 to any not dst-port 53,161 out via em1

01000 969141 302656510 nat 10 ip from 172.16.0.0/16 to any out via em0
02000 1597013 1629202239 nat 10 ip from any to 1.2.3.4 in via em0