[tjohns]

Yes, that is generally/approximately correct. I'm not sure precisely how it's implemented on the public side, but you're placed into a seperate VLAN that enforces the captive portal. Traffic from the public WiFi network is isolated from the subscriber's traffic.

[ClumsyPilot]

That does not mean it uses a different public IP address that communicate with the rest of the intermet, I have seen dozens of such public/private wifi systems, abd never seen one with a separate public IP

[croon]

That doesn't at all answer GPs question though. That they're isolated LANs doesn't at all answer what WAN address they use. If no other indication it probably uses the same.

I have multiple VLANs at home, and I only have one WAN IP.

[compsciphd]

https://www.reddit.com/r/Comcast/comments/67orc4/xfinity_wif...

for what its worth: claims to have tested and says they are different public IPs

[webmaven]

Okay, so what do you get if you lookup which customer is associated with the public IP?