Tech­niques which decides if a new device can join the nor­mal or a spe­cial network. A cap­tive por­tal forces a client to an authen­ti­ca­tion page. After authen­ti­ca­tion in a nor­mal low-secu­ri­ty envi­ron­ment (where you can­not assume pre­con­fig­ured sys­tems) the authen­ti­ca­tion is usu­al­ly grant­ed to a com­bi­na­tion of MAC and IP. There­fore, try to sniff valid…