Actually I have a case where I should able to detect the mobile phones and get some data about the device available in my network range without connecting to the network.
I have seen somewhere that a smart-phone continuously transmits hello packets so that we can detect that device when it comes in our network.
Can a smart-phone send hello packets continuously? if so.. how can we detect them and get some data about that device?
I believe spartan is talking about Wifi "probe requests". You can capture these using wireshark when your wireless adapter is set to "monitor mode".
You can filter for them using the following syntax:
wlan.fc.type_subtype == 0x04
These are managment frames and are basically frames sent from your client to find out which wireless networks / AP are around.
More information can be found on Hak5's episode on probe requests.
If you are talking about these other "hello packets", such as automatic pings or so, then Wireshark is still your friend.
The closest thing to a 'hello' packet concept in a smart phone, which mostly use TCP/IP, will probably be a DHCP-DISCOVER broadcast and then subsequent ARP requests, presuming it is active on the network.
Most smart phones will probably respond to ping, too, so presuming you have control over DHCP on the network, once you know its IP address, send pings to check it's still alive. To determine more information about it, standard TCP/IP discovery tools can be used such as nmap.
There are more advanced methods of determining more information about wifi enabled smartphones on your network. For further reading, check out https://www.google.co.uk/search?q=smartphone+network+fingerprinting
Some of the results are heavy reading PDFs, but you'll get through them if you find this interesting.
There is a framework called snoopy which does this. I haven't really had a look into it but it may be what your looking for.
Hope this helps
