http://www.tcpdump.org/ <--官方網站
http://www.tcpdump.org/tcpdump_man.html <-- manual page
tcpdump can read all or certain packets going over the ethernet.
tcpdump is often used to save the network traffic in a file.
簡單來說…就是可以將流經網卡的封包抓取下來…存成檔案加以分析就對了~
