Your firewall protects nothing — Zero Trust checks every packet like it came from the Internet

NIST published SP 800-207 in August 2020, the Biden administration mandated Zero Trust for all US federal agencies in January 2022, and Google has been running BeyondCorp internally since 2011 without a VPN. If your network security still relies on the assumption that a packet is clean because it originated on the LAN, you have already lost.