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POE::Component::Server::NSCA - a POE Component that implements NSCA daemon functionality


version 0.12


  use strict;
  use POE;
  use POE::Component::Server::NSCA;
  use POSIX;

  my $nagios_cmd = '/usr/local/nagios/var/rw/nagios.cmd';

  my $nscad = POE::Component::Server::NSCA->spawn(
        password => 'moocow',
        encryption => 1,

        package_states => [
           'main' => [qw(_start _message)],

  exit 0;

  sub _start {
     $poe_kernel->post( $nscad->session_id(), 'register', event => '_message', context => 'moooo!' );

  sub _message {
     my ($message,$context) = @_[ARG0,ARG1];

     print "Received message from: ", $message->{peeraddr}, "\n";

     # Send the check to the Nagios command file

     my $time = time();
     my $string;

     if ( $message->{svc_description} ) {
        $string = "[$time] PROCESS_SERVICE_CHECK_RESULT";
        $string = join ';', $string, $message->{host_name}, $message->{svc_description}, 
                    $message->{return_code}, $message->{plugin_output};
     else {
        $string = "[$time] PROCESS_HOST_CHECK_RESULT";
        $string = join ';', $string, $message->{host_name}, $message->{return_code},

     print { sysopen (my $fh , $nagios_cmd, POSIX::O_WRONLY) or die "$!\n"; $fh } $string, "\n";



POE::Component::Server::NSCA is a POE component that implements NSCA daemon functionality. This is the daemon program that accepts service check information from remote machines using send_nsca client or POE::Component::Client::NSCA.

The component implements the network handling of accepting service check information from multiple clients, but doesn't deal with submitting the service checks to Nagios. Instead you will be provided with the service check results as events and decide how to deal with the results as you see fit.

It is based in part on code shamelessly borrowed from Net::Nsca and optionally supports encryption using the Mcrypt module.



Takes a number of parameters, mandatory ones are indicated:

  'password', password that should be used to encrypt the packet, mandatory;
  'encryption', the encryption method to use, see below, mandatory;
  'alias', set an alias on the component;
  'address', bind the listening socket to a particular address, default is IN_ADDR_ANY;
  'port', specify a port to listen on, default is 5667;
  'time_out', specify a time out in seconds for socket connections, default is 60;
  'access', an arrayref of Net::Netmask objects that will be granted access, default is 'any';

Returns a POE::Component::Server::NSCA object.

The 'encryption' method is an integer value indicating the type of encryption to employ:

       0 = None        (Do NOT use this option)
       1 = Simple XOR  (No security, just obfuscation, but very fast)

       2 = DES
       3 = 3DES (Triple DES)
       4 = CAST-128
       5 = CAST-256
       6 = xTEA
       7 = 3WAY
       8 = BLOWFISH
       9 = TWOFISH
       10 = LOKI97
       11 = RC2
       12 = ARCFOUR

       14 = RIJNDAEL-128
       15 = RIJNDAEL-192
       16 = RIJNDAEL-256

       19 = WAKE
       20 = SERPENT

       22 = ENIGMA (Unix crypt)
       23 = GOST
       24 = SAFER64
       25 = SAFER128
       26 = SAFER+

Methods 2-26 require that the Mcrypt module is installed.



Returns the POE::Session ID of the component.


Terminates the component. Shuts down the listener and disconnects connected clients and unregisters registered sessions.


Access to the POE::Wheel::SocketFactory method of the underlying listening socket.


These are events from other POE sessions that our component will handle:


This will register the sending session. Takes a number of parameters:

   'event', the name of the event in the registering session that will be triggered, mandatory;
   'context', a scalar containing any reference data that your session demands;

The component will increment the refcount of the calling session to make sure it hangs around for events. Therefore, you should use either unregister or shutdown to terminate registered sessions.


This will unregister the sending session.


Registered sessions will receive events with the following parameters:


ARG0 will contain a hashref with the following key/values:

 'version', the version of NSCA protocol in use. Will be 3;
 'host_name', the hostname for which the check is applicable;
 'svc_description', the service description, not applicable for host checks;
 'return_code', the result code of the check;
 'plugin_output', any output from the check plugin;
 'peeraddr', the IP address of the client that gave us the check information;
 'peerport', the IP address of the client that gave us the check information;
 'crc32', the checksum provided by the client;
 'checksum', the checksum as the poco calculated it;
 'timestamp', the clients timestamp;

ARG1 will contain the value of the 'context' that was specified ( if applicable ) when the session registered.


Based on Net::Nsca by P Kent

Which was originally derived from work by Ethan Galstad.







Chris Williams <>


This software is copyright (c) 2021 by Chris Williams, P Kent and Ethan Galstad.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.