fping -s 选项

# fping -s -g 150.*.*.0/24 254 targets 8 alive 246 unreachable 0 unknown addresses 246 timeouts (waiting for response) 992 ICMP Echos sent 8 ICMP Echo Replies received 0 other ICMP received 72.6 ms (min round trip time) 92.2 ms (avg round trip time) 116 ms (max round trip time) 27.519 sec (elapsed real time) 可以看出对于无法到达的主机，每个发送4次Echo request 也就是说尝试一次之后，不成功，又重新试3次 因为992-8 = 984 ， 984 / 246 = 4