Re: ping check bug?

Paul Fox writes:

> i see that there's code in CheckHostAlive to do an initial
> "wakeup" ping, before a second "real" ping.  this should help
> my situation.  unfortunately, the code as written returns from
> CheckHostAlive immediately upon an error return from the
> execution of $pingCmd, even for the initial wakeup ping.  this
> renders the wakeup ping useless -- we'll never try the second
> ping.  the fix is simply to remove the "return -1" from that
> clause:
> 
>     #
>     # Do a first ping in case the PC needs to wakeup
>     #
>     $s = $bpc->cmdSystemOrEval($pingCmd, undef, $args);
>     if ( $? ) {
>       print(STDERR "CheckHostAlive: first ping failed ($?, $!)\n")
>                       if ( $bpc->{verbose} );
>       # fall through (was "return -1;")
>     }

My original intent was to get a more accurate round-trip time by
doing two pings and timing just the second ping.  So I consider
a first ping failure as fatal.

But I'm ok making this change.

> that's makes it much better, but it's not quite enough for my
> situation -- it always seems to take at least two "icmp redirect"
> responses before the pings start going to the right place.  this
> means that the single wakeup ping isn't enough -- i need at least
> two.  i've added another wakeup ping before the final ping (three
> altogether) and this seems to be reliable.
> 
> so, a request:  can that code be changed to make multiple
> attempts to ping the host, rather than just two?  i'm thinking a
> loop that tries, say, 10 times, before giving up.  that'd be a
> lot more robust...

I would rather not do it 10 times, since, for example, a DHCP
pool search would be a lot slower.

I recommend simply writing your own shell or perl script that does
several pings and point $Conf{PingCmd} at your script.

Craig


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