ICMP is not a reliable network protocol. IP is allowed to drop the
packets without notice. The only way to detect the case is when too
much time has elapsed without a response---$timeout is reached.
Enqueuing your request in the event queue is not the same thing as
sending an ICMP packet. post() may succeed where the ping fails.
--
Rocco Caputo - rcap...@pobox.com
On Apr 19, 2009, at 12:44, Stuart Kendrick wrote:
If the OS fails to execute a ping, does there exist a mechanism for
the OS to tell POE about that? And for me to 'notice' such an
incident?
I was hoping that checking the return value on a 'post' would do
that ... but thus far, no dice (i.e. the box on which my script is
running intermittently fails to emit pings, but by script doesn't
log anything.)
[...]
# "Pinger, do a ping and return the results as a pong event. The
# address to ping is $addr."
$result = $kernel->post( 'pinger',
'ping',
'pong',
$addr,
$timeout,
);
log_error("Problem pinging $addr: $!") unless $result;
[...]
From http://search.cpan.org/~rcaputo/POE-1.004/lib/POE/Kernel.pm#post_DESTINATION,_EVENT_NAME_
[,_PARAMETER_LIST]
"post() returns a Boolean value indicating whether the message was
successfully enqueued. If post() returns false, $! is set to explain
the failure:"
--sk
Stuart Kendrick wrote:
my favorite pinging application (in-house app, uses
POE::Component::Client::Ping) intermittently reports a rash of
missed replies. happens roughly the same time each night; the
condition lasts for several minutes
