A customer is running their PCs behind their VoIP phones. Nothing unusual, most VoIP phones I know have an embedded ethernet switch, so that you only need one cable to connect PC and VoIP phone to your network. [caption id=“attachment_3876” align=“alignnone” width=“640”] Martinelle/ pixabay.com/ Creative Commons CC0[/caption] As part of a network security project, my colleague and I implemented IEEE 802.1X port-based Network access control at one of our customers networks.