Practice what they preach. Don't tell them anything they don't need to know. Don't join their WiFi. Don't share information about the organizations you have wo

Practice what they preach. Don't tell them anything they don't need to know. Don't join their WiFi. Don't share information about the organizations you have worked with in the past. That's and make sure you are familiar with the concepts of OpSec. Typically in a 30 minute interview the extent of the technical questions are going to be limited to concepts not practice. I can't imagine a 30 minute interview will require you to setup a firewall, or configure a router.