I see it being a little bit of a security issue, if you are accepting these messages from the internet. I know you can use 
smbclient -M <hostname>
to send a message from a linux to windows machine on the same lan. I don't know if you could get it to work over the internet, or even if you can, what kind of problems it may cause, but you can try it out.

In reply to Re: How to send popup message? by tcf22
in thread How to send popup message? by ralijani

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