[collectd] ping plugin is not works in some cases (Linux)

[Sergey]

Hello.

I attempt to use ping plugin and I found that it is not works
in incomprehensible cases. I have 3 systems with identical 
configurations. The one works and other two don't.

collectd 5.9.1, identical rpm package. Configuration is fully same:

<Plugin ping>
        Host "localhost"
</Plugin>

The only difference is a hostname. The working system has real 
hostname with full DNS support, other two is a notebooks with
local defined hostnames. I don't see any other difference.
cpu, load and memory plugins works. Can anyone suggest anything?

-- 
Regards,
Sergey