Network fingerprinting exists for a while and some methods such as JA3 have achieved wide adoption across the industry. Introducing network fingerprinting into login flows can help you stave off attackers. However, there are various challenges that you need to overcome: technical, organizational and regulatory. In this talk we will take a look at the opportunities that network fingerprinting provides us. We will go through the various challenges that can arise and discuss possible ways of tackling them. I will draw from insights gathered at 1&1 Mail & Media - the company behind web.de, GMX and mail.com. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://c3voc.de