First, I declare that this Article applies to: retrieve the dialing Internet password of your home (which means that you can physically access the computer/router used for dialing. But it does not apply to: cracking a neighbor's wireless network-based on my existing knowledge, you need aircrack-ng, reaver-wps, and a powerful wireless network card to brute force crack the vro login password (non-dial password). We recommend THC-Hydra, which is efficient and powerful. There is even a graphical interface. Body. The principle of cracking is simple: Generally, the home router will take turns to try different authentication protocols, while the PAP Protocol needs to authenticate the client to send the user name and password in plaintext. Based on these two points, we only need to build a pppoe server that only accepts the PAP authentication, and then let the router authenticate it to capture packets with the dial-up username and password. Key points: Install rp-pppoe (put in the ppp package under ubuntu) write the server configuration file with the focus of require-pap and login: https://github.com/cherrot/dotfiles/blob/master/pppoe-server-options running pppoe-server, A pppoe authentication server is running: sudo pppoe-server-F-I eth0-L 100.0.0.1-R 100.0.0.100-N 20-O/PATH/TO/YOUR/pppoe-server-options start wireshark, listen to the Ethernet interface and unplug the network cable of the WAN port of the router. Switch to the network cable connected to your computer and find the authentication data frame containing the user name and password. The task is complete!