How to Determine if a Host Is Losing Packets

If you suspect that a machine might be losing packets even though it is running, you can use the s option of ping to try to detect the problem.

On the command line, type the following command.

% ping -s hostname

ping continually sends packets to hostname until you send an interrupt character or a timeout occurs. The responses on your screen will resemble:

PING elvis: 56 data bytes
64 bytes from 129.144.50.21: icmp_seq=0. time=80. ms
64 bytes from 129.144.50.21: icmp_seq=1. time=0. ms
64 bytes from 129.144.50.21: icmp_seq=2. time=0. ms
64 bytes from 129.144.50.21: icmp_seq=3. time=0. ms
.
.
.
----elvis PING Statistics----
4 packets transmitted, 4 packets received, 0% packet loss
round-trip (ms) min/avg/max = 0/20/80   

The packet-loss statistic indicates whether the host has dropped packets.

If ping fails, check the status of the network reported by ifconfig and netstat, as described in "ifconfig Command" and "netstat Command".