ping, every 4th packet not reported on

[marthter]

Hellooo Leenooks users...

I've noticed this for years but finally I can't stand not understanding 
it any more.  Hopefully someone on here who's better versed with Linux 
than me can set me straight...

Why is every 4th packet not mentioned in ping results when pinging a 
non-live address?

i.e. in the icmp_seq numbers below, they go: [no 1], 2, 3, 4, [no 5], 6, 
7, 8, [no 9], 10, 11, 12, ...

It seems like the missing numbers will start randomly at either 1, 2, 3, 
or 4, but then from there onwards it is EVERY 4th one consistently for 
hundreds or thousands of packets if I let it go.

What does it mean?

Thanks in advance.

Martin


[martin at grand ~]$ ping large
PING large.example.com (192.168.11.11) 56(84) bytes of data.
 From grand.example.com (192.168.11.22) icmp_seq=2 Destination Host 
Unreachable
 From grand.example.com (192.168.11.22) icmp_seq=3 Destination Host 
Unreachable
 From grand.example.com (192.168.11.22) icmp_seq=4 Destination Host 
Unreachable
 From grand.example.com (192.168.11.22) icmp_seq=6 Destination Host 
Unreachable
 From grand.example.com (192.168.11.22) icmp_seq=7 Destination Host 
Unreachable
 From grand.example.com (192.168.11.22) icmp_seq=8 Destination Host 
Unreachable
 From grand.example.com (192.168.11.22) icmp_seq=10 Destination Host 
Unreachable
 From grand.example.com (192.168.11.22) icmp_seq=11 Destination Host 
Unreachable
 From grand.example.com (192.168.11.22) icmp_seq=12 Destination Host 
Unreachable
^C
--- large.example.com ping statistics ---
12 packets transmitted, 0 received, +9 errors, 100% packet loss, time 
11862ms
pipe 3
[martin at grand ~]$

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://gtalug.org/pipermail/legacy/attachments/20100322/e14810a6/attachment.html>