#!/usr/bin/perl -w

use strict;
use Net::Ping;

my $fetchmail = '/usr/local/bin/fetchmail';
my @fetchmail_args = ('-s', '-t', '60');

my $hostname = 'hostname'; # an external host
my $timeout = 3;

my $p = Net::Ping->new('udp', $timeout);

if( $p->ping($hostname) ){
   print "$hostname is alive.\n";
   # exec($fetchmail, @fetchmail_args);
}else{
   print "$hostname is unreachable.\n";
}