Net::NetSend - Perl extension for sending Windows Popup Messages


  use Net::NetSend qw(:all);
  my $target_netbios_name;
  my $source_netbios_name = "mypc";
  my $target_ip = "";
  my $message = "Hello World!";
  my $debug = 0;  
  $target_netbios_name = getNbName($target_ip, $debug);
        die "No netbios name found: $@\n";

  my $success = sendMsg($target_netbios_name, $source_netbios_name, $target_ip, $message, $debug);
  print ($success ? "Delivery successfull\n" : "Error in delivery! \n$@\n");


This module implements a client interface to the Windows Messenger Service, enabling a perl5 application to talk to windows machines. This is a pure Perl implementation that approximates the "net send" command on Windows.


The source netbios name may be chosen freely and does not need to match your real netbios name.

Both target netbios name and target IP are needed when sending a message. However, since version 0.12 this module includes a routine to lookup the netbios name of a given IP. A lookup procedure vice versa is not implemeted in this module yet. You're welcome to add it and send me a patch. If noone else volunteers for this task, I intend to do this myself when I've got some spare time for it.

The target IP can be a numerical IP like it is shown above or a hostname like host.domain.tld.

The message can be any arbitrary string. If it is greater than 4000 chars the message will still be delivered but truncated to 4000 chars. If you _really_ want to send more text than 4000 chars you can split your message into parts of the respective maximum of 4000 chars and call sendMsg() for all parts consecutively. In this case be sure to have a look at the CAVEATS section a few lines down this page.

Debug is intended to print more status information in case of difficulties. In general it works like a "verbose" switch. The parameter "debug" is optional and defaults to 0. It can be one or zero. Zero means "No, don't print debug messages.", one means "Yes, please print debug messages to STDOUT."

By default (debug off), sendMsg() does not print anything in case of success. In case of a failure it prints an error message.


This module expects answers from the remote machine when a connection has been successfully established. If the remote machine stops responding after the connection has been established it might hang for some time (forever?). You can use the alarm function to be sure this does not happen. As this situation is extremely rare you probably don't need it. But if you intend to send thousands of messages at once you should probably do it.

Be advised that you need a short pause (one second is more than enough) between two messages to the same machine. No pause is needed between messages to different machines.

If sendMsg() fails it will call die(). If you don't want your program to exit when sending a message to one machine fails (because you want it to try delivering the message to another machine) you have to encapsulate the call to sendMsg() in an eval statement.


None by default. :all exports sendMsg() and getNbName()


This module was tested with Windows XP, Windows 98, Windows NT and Linux. It should work on any other operating system as well. Drop me a note if you encounter errors, giving the exact circumstances of the failure and a listing of the output with debug enabled. A packet dump would be helpful, too.

Maximum Message size is 4000 bytes.


new in 0.02


bugfix last message of multi block message


check MBM text packet return codes for success

    new in 0.04


    check restriction of 4021 chars maximum message length


    Warnings AF_INET / SOCK_STREAM eliminated


    check MBM END packet return codes


    extra function for error checking in SMB return packets


    sendMsg now returns success/error code

    new in 0.05


    abort if session request fails


    set $@ if error occurs


    change some global vars to local ones

    new in 0.06


    comment cleanup


    add flexible debug messages

    new in 0.07


    useless "no strict" outcommented


    fixed a bug that happened when splitting messages containing newlines


    added documentation

    new in 0.08


    added contact information


    bugfix for error handling $@


    module renamed to Net::NetSend


    argument count check


    4022 bytes -> 4021 chars

    new in 0.10


    POD documentation

    new in 0.11


    Cut message size to 4000 chars. This is more safe. Before, sending could fail if message length plus source netbios name plus target nebios name were greater than 4032 chars.


    An accidentally German error message was translated to English and extended to give more information about the error. Thanks to Tom Metro for reporting this and some other things.


    Documentation about caveats added.


    Bugfix for accumulating error texts as reported by brae.charles at (Thanks!)


    POD documentation extended.


    Error messages improved to give more information about the error.

    new in 0.12


    Added capability of looking up netbios names by IP address.


    Minor code adjustements.


Florian Greb, <>


Copyright (c) 2004-2005 Florian Greb. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

8 POD Errors

The following errors were encountered while parsing the POD:

Around line 785:

You can't have =items (as at line 789) unless the first thing after the =over is an =item

Around line 812:

You can't have =items (as at line 816) unless the first thing after the =over is an =item

Around line 831:

You can't have =items (as at line 835) unless the first thing after the =over is an =item

Around line 846:

You can't have =items (as at line 850) unless the first thing after the =over is an =item

Around line 865:

You can't have =items (as at line 869) unless the first thing after the =over is an =item

Around line 892:

You can't have =items (as at line 896) unless the first thing after the =over is an =item

Around line 903:

You can't have =items (as at line 907) unless the first thing after the =over is an =item

Around line 941:

You can't have =items (as at line 945) unless the first thing after the =over is an =item