The invention presented relates to the field of network communication, and disclosed a method and means for retrieving Internet authentication information technically. This method comprises: connect the original functioning network device and receive the packets sent by it; extract the communication data sent to the ISP from those packets, and analyze it to figure out the authentication information needed to access the Internet; record that authentication information, and use or display it whenever adequate. The invention presented can help users retrieve the required authentication information without the need for help from ISPs, which can be very convenient for users who forgot his authentication information when trying to access the Internet or to replace the old network device with the new one.