# Is this question acceptable for this site?

Is there any way to send a popup message from a Linux systen to a "random" laptop/tablet/mobile linked to my Wireless network ? For example, if I let my WLAN open and I see a not recognized computer connected to it, is there anyway to send to that device a message ?

On the other hand, if I am connected to someone else open network and they may or may not be aware that their network is open, can I send them a message warning that I am accessing their network?

Is this question acceptable for this site?

PS: I have no practical application for this is just curiosity.

Yes, I would consider that as a valid question. You have a computer problem need to inform other users on the network looking for a solution on how to do that.

And well, I felt like answering:

You can only do this if the computer provides a service to do this, which is often enabled by default.

You could hook up into their network traffic, but that would be considered illegal; just accessing their network is actually already illegal as well. Unless you live somewhere where it is not, YMMV...

But perhaps there are interesting approaches to this that might work.

• Hi Tom thanks a lot for the information. So it seems that this is a reasonable question for the main site. – Leandro Mar 29 '12 at 23:05
• @Leandro: Yes, there is no problem just trying. I don't see how it does not adhere to the Super User FAQ and it really feels welcome... – Tamara Wijsman Mar 29 '12 at 23:08
• You forgot the part where he's already asked on another site and should just wait for migration. – Daniel Beck Mar 31 '12 at 3:30
• @DanielBeck: The Stack Exchange team forgot a way to check for cross-site duplicates, I wouldn't be surprised if this question also made its way to security.stackexchange.com... – Tamara Wijsman Mar 31 '12 at 9:43