StreetPass

StreetPass is a feature that allow your 3DS to connect with other 3DS using WiFi in standby mode. It can be used to share Mii(s) on Mii Plaza for example.

Using Wireshark tool with a WiFi card in monitor mode allow you to see the data used to scan for other 3DS in the range. The below is a broadcast probe request from an 3DS while in standby mode, with SSID "Nintendo_3DS_continuous_scan_000". When in "active" mode, 3DS sends probe requests with arbitrary SSID strings, like "ic[kSvm9s@*cYD>/~IEVj\(fGG;qDo8j".

 0000   00 00 1a 00 2f 48 00 00 19 7d 19 de 2a 00 00 00  ..../H...}..*...
 0010   12 16 9e 09 a0 00 c9 02 00 00 40 00 00 00 ff ff  ..........@.....
 0020   ff ff ff ff da 6b f7 22 f3 77 ff ff ff ff ff ff  .....k.".w......
 0030   40 77 00 20 4e 69 6e 74 65 6e 64 6f 5f 33 44 53  @w. Nintendo_3DS
 0040   5f 63 6f 6e 74 69 6e 75 6f 75 73 5f 73 63 61 6e  _continuous_scan
 0050   5f 30 30 30 01 08 82 84 8b 0c 12 96 18 24 32 04  _000.........$2.
 0060   30 48 60 6c dd 15 00 1f 32 01 11 05 00 02 08 00  0H`l....2.......
 0070   00 f0 08 c8 34 6e 05 0f c9 c6 80 5b 6f bc 5a     ....4n.....[o.Z