in reply to is there script to detect if remote machine is alive/reachable w/o using Net::Ping?

Im currenlty using a Redhat Linux and the PING command there seems to also "HANG" on unreachable machines

Did you specify a timeout period for ping? You can use -t to tell ping when you want it to exit. Here's some code that returns true if the remote machine pings at least once in 7 seconds:

sub ping {
  my $ip = shift;
  my $p = `/sbin/ping -c 5 -t 7 $ip | /usr/bin/grep 'packet loss'`;
  unless ( $p =~ /(\d+)% packet loss/ ) {
    die ( "Bad Response:\n$p\n" );
  }
  my $loss = $1;
  print "Loss = $1 ";
  return ( $loss != 100 );
}

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Re: Re: is there script to detect if remote machine is alive/reachable w/o using Net::Ping?
by perigeeV (Hermit) on Jun 07, 2002 at 00:41 UTC

    Are you on RedHat? iputils-ss001110 uses -t for time-to-live. I've got -w for timeout. Oh well, no matter.


[reply]
      tnx very much guys! i really appreciated the help. even though my question was not specific. im really sorry about it. my question shouldve been like this: 
      In general IO::Socket process (regardless of which socket and what typ
+e of socket to use) what should be the recommended process to detect 
+if the remote machines are alive/reachable if you dont want to put a 
+DIE command after the IO::Socket::INET->new() process? (of course, to
+ avoid HANG and probably you would have other codes to execute after 
+the socket connect process...)

      [download]
      The only thing I thought about at that time was PING. And yes I did forget to check the man pages, sorry for that. heres what i did.: 
      sub doit
{
$host="$aa.$bb.$cc.$dd";
$port="23";
$fnd="";


$pong=`ping -c 3 $host -v`;    #is there really a "-t" option here?
$fnd=($pong=~m/(...)%/gi);
$xcd=$1;  

 if ($xcd!=100)
 {    

$remote = IO::Socket::INET -> new (
             Proto => "tcp",
             PeerAddr => $host,
             PeerPort => $port,
             Timeout => 1
             );
$| = 1;


if ($remote) 
{
close $remote;
print "Socket ready...";
}
else
{
print "Try again!";
}
}  
 }

      [download]
      tnx really a lot for helping me. but i do have one inquiry though. "Is there a way to detect remote machines if they are alive/reachable w/o using NET::Ping and the shell command /sbin/ping?" Hopefully something like a socket command. thank you very much to all those who helped me. Lovelots and *mwah*, Cherry.
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