tcpdump 选项 vnn 的含义是什么

what's the meaning of tcpdump option vnn

这是一个 tcpdump 命令:

# tcpdump -i eth0 -vnn  udp

-i表示接口 eth0 是接口名称 udp 表示 upd 协议, 但, 这个选项[-vnn]是什么意思?

'-vnn' 与将 -v 和 -nn 指定为两个单独的选项相同。来自 tcpdump 手册:

-v When parsing and printing, produce (slightly more) verbose output. For example, the time to live, identification, total length and options in an IP packet are printed. Also enables additional packet integrity checks such as verifying the IP and ICMP header checksum.

-nn Don't convert protocol and port numbers etc. to names either.

请注意,-nn 也意味着 -n。