Beating CGNAT: Reaching a Homelab With No Public IP

Thu, 15 Aug 2024 09:15:00 +0000

The first sign is usually a service that used to be reachable from outside the house and suddenly isn’t. You check the router, the port forward is still configured exactly as it was, the local service is up, and yet nothing gets through. Then you check what IP address your router thinks it has on the WAN side, compare it against what a “what’s my IP” site says from outside, and they don’t match. That mismatch is CGNAT — Carrier-Grade NAT — and once an ISP has put you behind it, port forwarding is not broken, it’s simply irrelevant, because your router was never handed a public address to forward a port on in the first place.

Cgnat - vo.rs

Beating CGNAT: Reaching a Homelab With No Public IP