I've been curious about how the Xfinity WiFi guest network operates. Can someone explain it in simple terms? I hear a lot about VLANs, but I want to know if it's all about those or if there's more to it. How does Comcast manage to allocate two separate external IPs to their boxes for this purpose? What security measures are in place to protect this network? Also, I've seen videos about people hacking old 3G boosters; I'm wondering what kind of technology can be used in this context?
4 Answers
The guest network operates using VLANs managed right on the router or router/modem combo. It doesn’t actually require two separate public IPs, although technically, they could use them. What happens is that the two networks—guest and main—are kept isolated from each other on the device.
I checked once, and it looked like it had a separate IP from my main network.
This is definitely something that could go in forums like r/techsupport or even r/comcast for deeper discussions.
Honestly, this might fit better in conversations on forums like AskReddit, since the question seems broader than technical support.
To manage separate external IPs, Comcast operates similarly to having a block of public IP addresses allocated to a firewall. This way, they can efficiently distribute different IPs to different networks without needing multiple physical connections.
They do use two independent networks; the guest network is capped at lower speeds, around 20-50mbps, and they might have different external IPs as well.