A question if to worry in transmissions of data for air is the security, therefore, had been implemented to these standards the protocol to cipher the data to be transmitted, WEP (Wired Equivalent Privacy), and successively WPA (Wi-Fi Protected Access) that it corrects imperfections of its predecessor. Some programs exist to capture information of nets without wire, as the Netstumbler the Kismet, but they also can help administrators to monitor the net. The attacks the nets without wire always reach the points most vulnerable of the net that are the concentrators and the customers, in what the administrators must apply all the cabveis measures of security and always have the attention redoubled for these two elements. Word-key: Wireless nets. Security. Vulnerabilities.