Your ISP's router may be broadcasting a second Wi-Fi network for strangers

Published Oct 30, 2026, 2:31 PM EDT Jasmine is Software and PC Hardware Author at XDA with years of tech reporting experience ranging from AI chatbots right down to gaming hardware, she's covered just about everything. Whether it's breaking news about the latest AMD NPUs or creating video tutorials on social media platforms, Jasmine has contributed to the world of AI and tech in a variety of ways including interviewing the CEO of Razer, AMD's Director of Product Marketing and the VP of Lenovo. Passionate about gaming and PC technology, she has built countless computers, keyboards and other peripherals - knowing them inside and out. Millions of subscribers plug in an all-in-one gateway provided by a lot of major ISPs, assuming its wireless radios exclusively service their private household devices. However, if you scan local 2.4GHz and 5GHz RF channels, you will often reveal secondary open public networks originating from the exact same physical radio hardware and MAC address block, using separate BSSIDs. ISPs routinely turn residential gateway hardware into public Wi-Fi hotspots by default, while segmenting them at the logical network layer via VLANs. This practice consumes local wireless airtime, alters gateway thermal/power profiles, and can strip network control away from you. ISPs try hard to stop guest affecting you There is logical network segmentation How do dual-BSSID Wi-Fi hotspots actually work? ISPs provide Wi-Fi hotspots to their customers, and a lot of the time this comes at the expense of the router that it's originating from, despite attempts from your ISP to ensure you don't notice. Modern Wi-Fi access point chips assign multiple virtual access point interfaces, each with its own distinct BSSID and SSID, to a single physical 2.4GHz, 5GHz, or 6GHz wireless radio card. The router broadcasts separate beacon frames for your private network and the public ISP hotspot it's generating over the exact same physical antenna array and channel frequency. There is logical network segmentation so traffic on the public guest SSID is isolated at Layer 2 using virtual local area networks or VLANs. Public client traffic doesn't hit your private subnet or local DHCP server. Instead, it's encapsulated in a GRE, or generic routing encapsulation, tunnel directly from the gateway back to the ISP's core network. ISPs configure quality of service queues to prioritize private subscriber traffic over public guest traffic, so your traffic is always prioritized. Public usage is metered separately on the ISP side and doesn't count towards your monthly data cap, if you have one, though it does share the same physical coaxial or fiber WAN pipe. But there are technical disadvantages Your airtime is being hogged There are some real technical disadvantages behind this happening. The first and most noticeable is airtime contention and channel coexistence. Wi-Fi relies on CSMA/CA, meaning carrier-sense multiple access with collision avoidance. This essentially means only one device can transmit on a specific frequency channel at a time. Even if public guest traffic is rate-limited at the WAN layer, strangers connected to your router still consume physical wireless airtime, which can increase packet contention and latency for your private devices on that same channel. There's also unnecessary beacon overhead and co-channel interference, as every additional SSID broadcast requires continuous 102.4ms beacon frames sent at the lowest basic data rate, which is often 6Mbps. In dense housing or apartment complexes where dozens of ISP gateways broadcast multiple SSIDs, this creates severe beacon clutter and significantly reduces available channel capacity across the 2.4GHz and 5GHz spectrums. And lastly, of course, are power draw, thermal loads, and memory reserves. Maintaining additional VAPs, managing public client association tables, and running continuous GRE tunnel encapsulation can significantly increase your router's processing overhead, especially for the Gateway System-on-Chip. This, as a result, will drive up internal device temperatures and background power consumption of your router. Audit your network And toggle off the feature There is a way to actually audit and reclaim your local spectrum and avoid your ISP using your router in this specific way. Before starting, the first thing you want to do is perform an RF audit using a Wi-Fi analyzer. There is a range of network analyzer tools available on both iOS and Android devices that will help you inspect any local BSSIDs. Match the MAC address of your private Wi-Fi network against adjacent open SSIDs. If the MAC address matches, except for the last octet or vendor prefix, the public network is originating from your router. Now that you know your router is being used in this way, the best next step is to disable guest or community hotspot features via your internet service provider's account portal. Because ISPs lock down local gateway firmware, turning off the public SSID often cannot be done without logging straight into your ISP's account portal. This is sometimes a web portal or a mobile app. Once you're in the settings, have a look at your advanced settings or your home hotspot settings and toggle off the public Wi-Fi/community hotspot feature. While toggling off this setting should rectify the issue, if you want to go a step further, you can put the ISP gateway into full bridge mode (which will disable its routing, NAT, and Wi-Fi radios entirely). Then you can connect your own standalone router or access point running open networking stacks or dedicated local hardware to ensure absolute control over all of your radio broadcasts, channel widths, and network security. It's not essential, but it gives you an extra layer of protection. Don't let strangers steal your airtime Toggle off this network setting Shared ISP community hotspots leverage customer-funded hardware and power to expand provider network footprints. While logically isolated from your private data, public Wi-Fi broadcasts unnecessarily consume wireless airtime, pollute the local RF environment, and complicate home network management. The best course of action is to audit your wireless spectrum, opt out of any provider-hosted public hotspots through your account portal, or bypass ISP gateway radios entirely by switching to dedicated personally owned networking hardware in bridge mode.