Method and device for preventing sniffing under WIFI environment

The present invention belongs to the wireless local area network security field and discloses a method and device for preventing sniffing under a WIFI environment. The method includes the following steps that: a data packet from a network is received; whether the source MAC address of the data packet is the MAC address of the data packet itself is judged, when the source MAC address is the MAC address of the data packet itself, whether the data packet is a De-Authentication message is judged; and when the data packet is the De-Authentication message, prompt information is sent to a terminal, so that the user of the terminal can be prompted that an sniffing client exists. With the method and device of the invention adopted, a discovery mechanism of network sniffing activities is realized; the risk of the being subject to network fraud of the user can be reduced by prompting the user that an accessed client conducts network sniffing activities; and therefore, the security of Internet surfing can be improved.