Is it possible that your server detects too many sessions from one ip and terminates the connection?

The problem is that the sessions are being made to different ip's in a concurrent fashion. So it's not just a (well not obviously at least) case of the destination server not allowing multiple simaltanoeus connections to it.

I can quite happily make as many active and non-active connections to the same ip without drama, by both hand and through the script.

could you please update the node with your Parallel::ForkManager code and I can run a quick check on my server?

A cutdown, very simple version of what I'm doing would be as follows:

#!/usr/bin/perl -w

use strict;
use Parallel::ForkManager;

my (@hosts) = ("192.168.0.1","192.168.0.2","192.168.0.3");
my $sshscript = "ssh.pl";

my $maxProbes = 3; # set this to one to do one at a time

my $pm = new Parallel::ForkManager($maxProbes);

foreach my $hostname (@hosts) {
        $pm->start and next;
        my $stdout = `./$sshscript $hostname`;
        print "$stdout\n";
        $pm->finish;
}
$pm->wait_all_children;
print "done\n";
[download]

with the snippet from the original node saved as ssh.pl and adjusted so that it set $host to the value of $ARGV[0]

Cheers for your time and reply.

Anth