Specify the number of data bytes to be sent. The default is 56,which translates into 64 ICMP data bytes when combined with the 8 bytes of ICMP header data. Only the superuser may specify values more than default. This option cannot be used with ping sweeps.
Record route. Includes the RECORD_ROUTE option in the ECHO_REQUEST packet and displays the route buffer on returned packets. Note that the IP header is only large enough for nine such routes; the traceroute(8) command is usually better at determining the route packets take to a particular destination. If more routes come back than should, such as due to an illegal spoofed packet, ping will print the route list and then truncate it at the correct spot. Many hosts ignore or discard the RECORD_ROUTE option.
在FreeBSD V1上监听FreeBSD V1和Mac之间的ICMP数据包
tcpdump -nex -ttt -i em0 -vnn icmp and \(host 192.168.146.1 and 192.168.146.141\)
ping -c 1 192.168.146.141
PING 192.168.146.141 (192.168.146.141): 56 data bytes
64 bytes from 192.168.146.141: icmp_seq=0 ttl=64 time=0.324 ms
--- 192.168.146.141 ping statistics ---
1 packets transmitted, 1 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.324/0.324/0.324/0.000 ms