Modern malware-proof version of NET SEND...?

[spinjector]

I know that NET SEND was being used by malware to send spam messages, and thus the Messaging service has been disabled by default since WinXP SP2.

Is there a modern equivalent? Or a utility that emulates it?

I'd like to be able to send instant popup message to everyone on the network at times when I need to reboot an app server and such.

[cluberti]

It might be worthwhile to have the service running, and the firewall on the PC allowing UDP 138 while on the domain, but when off having that port closed. You can configure both the service and firewall profiles in Group Policy.