Send messages to Iphone/Blackberry/Android on local Wifi without knowing number

I would like to send a messages to all iphones or blackberries or androids that are using my local wifi. Whether it be a bbm or a flash sms etc.... I am even willing to pay for texting etc....

Can I do so without knowing their number? Can I determine their number from their information (ie: mac address and or phone id) being sent a request for phone information?

I appreciate a开发者_JAVA技巧ny help. I have a feeling like it is not possible for many reasons, but I am curious....

Overall there is a way to do it, it's called "broadcasting" (or UDP broadcasting). Your wi-fi AP should support and allow it. You also must make sure Android, iOS and BB support this (but there is no reason why they shouldn't).

It looks something like this:

1. Install your custom app on all devices.
2. When device is connected to specific wi-fi access point, you send broadcast message "device X is connected, my address is XA, send messages to port XP" every several minutes. You also start listening for such notifications from other device.
3. If another device is connected, it will send "device Y is connected, my address is YA, send messasges to port YP". Device X will receive message from device Y, and device Y will receive message from device X.
4. When third device is connected, it sends "device Z is connected, my address ZA, send messsages to port ZP". This Z device will eventually receive messages from X and Y, while X and Y will become aware of Z device as well.

You'll probably need to implement simple TCP protocol in order to actually send messages from one device to another.

To summarize, you'll need to make discovery via UDP and communication via TCP. Those would be two different custom protocols. And it shouldn't be hard to implement. But you'll need to implement this for all mobile platforms you are interested in.

No, it's not possible (not for the Blackberry at least unless you're the NSA, since the BBMs are encrypted and operate on RIMs internal proprietary network before they even get out to any other carriers).

For the iPhone and the non-military Android phones, you'd just need to purchase your own private cell phone repeater/tower. That at least is feasible (although quite unpractical and highly risky), one guy did it successfully at a security conference with every participant's signed consent and with an independent auditor present, but he was lucky he didn't get himself arrested.

You see, by saying that you want to send an SMS, you're automatically implying that you wish to use the SMS infrastructure (which by definition doesn't even operate on wifi, it operates on the cell phone infrastructure).

That being said, if you control the wifi hot spot, you could do something else that might get you 60% of the way there. You could force everyone who utilizes your hot spot to go through an initial web page, and through that, you could communicate to them (although, please be aware, this is highly annoying to the user, at least it is to me especially on a phone).