Net::Telnet

GS has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks,

My script terminates if it can not telnet to the host in the array and does not loop through rest of the hosts in the array. How do I force it to continue to other hosts if it fails to telnet one host. here is the script:

use Net::Telnet;
@hosts = ("ncc1","ncc2","ncc3")

for ($x=0; $x <= $#hosts; $x++)
{
 $telnet = new Net::Telnet ( Timeout=>10,
                              Errmode=>'die');  
  $telnet->open("$hosts[$x]");
  $telnet->login('test', 'testuser');
  
  my @arr = $telnet->cmd('ifconfig -a');
  $telnet->close("$host");
  print "\n Probe - $host \n";
  print "\n @arr \n" ;
}
[download]

Edit by castaway - fix code tags

Comment on Net::Telnet Download Code

Replies are listed 'Best First'.
Re: Net::Telnet by davidj (Priest) on Jun 22, 2004 at 18:46 UTC
You need to change the value of `Errmode` when you initialize the `Net::Telnet` object. `Errmode=>'die'` tells the program to abort if there is an error (and failing to connect to a host is an error). I would suggest you do the following: `$telnet = new Net::Telnet ( Timeout=>10, Errmode=>'return');` [download] which will return undef if there is a connect failure. You can then test the return value of `$telnet->open("$hosts$x");` for undef and proceed as you wish. One possibility: `use Net::Telnet; @hosts = ("ncc1","ncc2","ncc3"); for ($x=0; $x <= $#hosts; $x++) { $telnet = new Net::Telnet ( Timeout=>10, Errmode=>'return'); $result = $telnet->open("$hosts$x"); if($result) { $telnet->login('test', 'testuser'); my @arr = $telnet->cmd('ifconfig -a'); $telnet->close("$host"); print "\n Probe - $host \n"; print "\n @arr \n" ; } else { print $telnet->errmsg . "\n"; } }` [download] I would suggest you read the Net::Telnet manpage Hope this helps, davidj	[reply] [d/l] [select]
Re: Net::Telnet by gri6507 (Deacon) on Jun 22, 2004 at 20:27 UTC
You could also do this (it should be quicker) Note: untested code `use strict; use Net::Telnet; foreach(@hosts){ if (!fork()) { my $telnet = new Net::Telnet ( Timeout=>10, Errmode=>'die'); $telnet->open($_); telnet->login('test', 'testuser'); my @arr = $telnet->cmd('ifconfig -a'); $telnet->close(); } }` [download]	[reply] [d/l]