I am worried that there is not really a benefit of doing that, just more noise and energy consumption.
Energy consumption is essentially the same, as it’s using the same radios.
For what it’s worth, I have several SSIDs, each on a separate VLAN:
- my main one
- Guest. Has internet access but is otherwise isolated - Guest devices can’t communicate with other guest devices or with any other VLANs.
- IoT Internet: IoT and home automation devices that need internet access. Things like Ecobee thermostat, Google speakers, etc
- IoT No Internet: Home automation stuff that does not need internet access. Security cameras, Zigbee PoE dongle (SLZB-06), garage door opener, ESPHome devices, etc
(to remotely access home automation stuff, I use Home Assistant via a Tailscale VPN)
Most of these have both 2.4Ghz and 5Ghz enabled, with band steering enabled to (hopefully) convince devices to use 5Ghz when possible.
This is on a TP-Link Omada setup with 2 x EAP670 ceiling-mounted access points. You can create up to 16 SSIDs I think.
Guest devices can’t communicate with other guest devices
How do you accomplish this isolation since they’re on the same subnet/broadcast domain? Is it a feature of the hardware you’re using?
A lot of access points, even consumer-grade ones, have this option. It’s usually accomplished via predefined firewall rules on the access points themselves.
Consumer-grade access points usually let you have just one isolated guest network, whereas fancier ones (Omada, Unifi, Ruckus, Aruba, etc) usually let you enable isolation for any SSID (ie the “guest network” is no different from any other SSID)
Isolated guest networks I get, but isolating guests from other guests on the same subnet/isolated net is what I haven’t seen.
For Unifi devices you setup a Virtual Network then assign the guests to that. https://help.ui.com/hc/en-us/articles/115000166827-UniFi-Hotspot-Portal-and-Guest-WiFi
I’m not seeing anything there that says guests can’t see other guests - quite the opposite.
guests connected to your Hotspot Portal will be isolated from all other networks except the one they are assigned to.
Guests on this network are able to access the internet, and communicate with the UniFi gateway to obtain a DHCP lease and resolve names using DNS
I suppose a switch could be configured to prevent traffic going to other ports, which is how I would assume this would have to be done. This functionality would have to exist in the access point, I guess?
Does UniFi have a feature to isolate devices from each other on the same subnet? Seems like it would require some kind of Layer 2 routing?
That was an amazing read. Thank you.
What do you say is the use case for separating guest Wi-Fi with the more “private” stuff on your network?
As far as I understand… Basically all communications, even inside a network, are encrypted… So I guess you do that to avoid someone trying to exploit some vulnerability?
I think the main benefit is that Guests devices on your network can’t find and exploit your own devices.
If you don’t trust the person, why give them access to your WiFi in the first place?
Remember that once you give the password out, they likely have the password from now on. They will always have access until you change the password.
No, a lot of local traffic is not encrypted, especially residential. No, residential probably doesn’t use much authentication or separation of privileges.
I don’t want my guests to be able to access my home server or Omada controller for example, or spread malware (their phone may have malware without them even knowing). Also, I give the guest wifi to people other than friends, like contractors. Phone reception is horrible at my house so I give them the wifi so they can use wifi calling.
I’m not sure that I understand the “more noise and energy consumption” part, since we’re still talking about the same router with the same connected devices.
But I do have multiple SSIDs on my router. One is explicitly for IoT devices, and they don’t have network access, so they are isolated from my computers, NAS, etc.
The more SSIDs being broadcast the more airtime is wastes on broadcasting them. SSIDs are also broadcast at a much lower speed so even though it’s a trivial amount of data, it takes longer to send. You ideally want as few SSIDs a possible but sometimes it’s unavoidable, like if you have an open guest network, or multiple authentication types used for different SSIDs.
Are we talking main + guest network, or 2,4GHz + 5GHz, or something else?
Why would you want to do this, anyway? Or, as I as a developer regularly have to ask our sales people: what do you actually want to achieve that led you to this question?
Here’s my use-case, I’m pretty sure the first 2 are pretty common (common enough to be supported by most OEM firmware):
- main LAN
- guest LAN (isolated from “main” but can access internet)
- IoT LAN (isolated from internet, can be accessed from “main”; prevents devices from phoning home)
But you don’t need several LANs for this. This can easily done with proper routing. A can access internet and internal network addresses. B can only access internet, and C can only reach internal addresses.
I’m curious. How would you identify who’s guest and who’s not in this case?
With multiple networks it’s pretty easy as they are on a different network.
It’s more like: I know people do this, but I don’t, so I wanted to see what was the reasoning behind these things.
Whether it has benefits is up to you, but from a technical perspective they’re as expensive as VLANs, so basically free. It’s the same receive and transmit radio, the only difference is that it broadcasts and responds to two network names at the same time. The maximum power consumption is the same: the max the radio will pull when at full load. The minimum power consumption has to be ever so slightly more since it needs to broadcast two network IDs, but those are measured in bytes and sent a couple times a second, it’s negligible compared to the cost of just running the radio.
