Hi,all i find that i only can inspect ip packet with netfilter hooks. if there are some hooks with which i can look deeply in other packets, i.e. ARP. Jinyi ===================================================== 姓名: 王金一 电话: (+86)10-58812325 单位: 中国科学院计算机网络信息中心 R&D 地址: 北京中关村南四街四号 邮编: 100080 email: jywang@xxxxxxx ----------------------------------------------------- Name: jinyi wang Phone: (86-10) 5881-2325 Division: R&D,Computer Network Information Center, Chinese Academy of Sciences Address: 4,4th South Street, Zhongguancun, Haidian District, Beijing, China Zip code: 100080 Email: jywang@xxxxxxx =====================================================