#!/usr/bin/perl -w
use strict;       
use Net::Telnet();

# ...
# ...

sub checkVersion {
  my $host = shift;    
  my $telnet = new Net::Telnet(Timeout => 10,
                            Prompt => '/-> $/',
                            Errmode => "return");

  if ( not $telnet->open($host) ){    
    # Telnet timeout for destination
    print "Telnet failed for address $host.\n";    
    $telnet->close;
    return 0;
  }
  # ...
}


for ( my $i = $ip_range_start; $i <= $ip_range_stop; $i++) {
  $host = "$ip_c_base.$i";    
  checkVersion($host);
}