CGNAT means your internet provider shares one public IP across many homes. Here’s how to tell if you’re behind it, which providers use it (Starlink, T-Mobile, Verizon 5G Home), why your VPN router still works, and how to get around it for port forwarding and remote access.

Double NAT happens when your router sits behind your ISP’s gateway and both translate addresses. Here’s what it breaks (gaming, port forwarding, remote access), what it doesn’t (streaming and VPNs), and how to fix it.