Net Send messages aren't being received even though I have followed the instructions about starting the Messenger service from the KB article: http://support.microsoft.com/kb/839018
Open Windows Explorer.
In the left pane, right-click My Computer, and then click Manage.
In the Computer Management window, expand Services and Applications in the left pane, and then click Services.
In the right pane, double-click Messenger.
In the Messenger Properties (Local Computer) dialog box, click the General tab.
On the General tab, select Automatic from the Startup type list, and then click Apply.
Under Service status, click Start, and then click OK.
Actually it should be the other way around:
The Alerter Service is dependent on the Messenger Service. They are both set to not start since Windows XP Service Pack 2.
And I think both Services are not supported on Windows Vista and above.
The Messanger Service appears to require the Alerter service. If you turn that on the net send messages will work.
(I am asking and answering my own question because I couldn't find any answer anywhere on the internet)
It also depends on the target. NET SEND will send to the first location matching... so if you send to a user, and that user is logged on more than one place, you get the idea. If you send to the computer, that generally works. However, NET SEND isn't a guaranteed delivery type of protocol. So if you're looking to depend on delivery, I'd go with something else.
Keep in mind that with Service Pack 2 on Windows XP came their firewall. I believe that the default configuration of the firewall blocks all net send traffic. This should be easy to test by toggling the firewall on and off. If this is your issue I DON'T recommend disabling it, but rather adding an exception in the firewall configuration to allow the net send traffic. The exception rule I believe is to allow TCP port 139, please note I believe that this port should already be opened up if you have "File and Printer Sharing" in the firewall configuration.
see these links for more info:
http://www.cezeo.com/tips-and-tricks/windows-xp-firewall/
http://support.microsoft.com/kb/330904
i think it is filtered by any firewall due to the spam that was spreading by that5-6 years ago