The IPv6 Nightmare and the Double NAT Trap: My Quest for True Connectivity
It all started with a seemingly simple problem. My home network, centered around a Xiaomi AX6000 router running its stock firmware, was supposed to support IPv6. I had enabled it, and indeed, the router’s WAN port proudly displayed a public IPv6 address. Yet, none of my devices – my computers, my phone, my game consoles – could get one. Accessing IPv6-only websites was impossible. Diving Deep into IPv6 and Network Structure After some initial head-scratching, research pointed towards a concept called Prefix Delegation (PD). In simple terms, my ISP assigns a block (prefix) of IPv6 addresses to my router, and the router is then responsible for distributing individual addresses from that block to my devices. The symptom – WAN gets an address, LAN doesn’t – strongly suggested PD was failing. ...