Setting up two wifi networks to share internet connection from one modem?

ThatLaloBoy · June 7, 2023

Hi everyone. Longtime LTT fan, first time posting here on the forum. I hoping to find a solution to my problem and since Reddit wasn't helpful, I'm looking to the good people of this forum to help this network noob.

Some context: We have Gigabit Fiber internet and a Wifi 6 router at home. Both my family and the house we rent behind our house use the same Wifi network because the local ISP refused to give the renters their own service and router. Everything worked for a while until we both started adding more devices to the network. Apart from the obvious security concerns, the network is starting to get crowded with multiple devices and it's also getting confusing to know what is what. Since both homes have an HP router, a Roku TV, and a bunch of other things it's happened multiple times where one person sends or starts casting things to the other's house and vice versa. And since I'm the IT member of the house, my family has asked me to "separate the wi-fi so our stuff and theirs doesn't mix together". I am very comfortable with PC hardware however I am a complete noob when it comes to network hardware.

Basically, I'm trying to setup two separate Wi-fi networks and have them share the same internet connection on our property. I tried switching the renters to the guest wifi however that doesn't allow for devices to connect to each other (which would be mainly casting to TV, sharing files over network, and printing). I was planning on just connecting an ethernet switch to two routers and just wiring it to the other house. However, someone pointed out to me that since my ISP only provides one IP address that only one router would get internet and the other wouldn't. They said that I either needed to make a setup that supports "multiple IP subnets" or "support for multiple VLANs". I asked for suggestions for devices or setups, but the person only said that most "prosumer and business routers support them". That's basically where I'm at.

Does anyone have any product recommendations or suggestions to make this work? I'd like to get some help from people who know more about this before I end up spending too much money on the wrong hardware. Thank you and have a great day.

LIGISTX · June 7, 2023

39 minutes ago, ThatLaloBoy said:

Hi everyone. Longtime LTT fan, first time posting here on the forum. I hoping to find a solution to my problem and since Reddit wasn't helpful, I'm looking to the good people of this forum to help this network noob.

Some context: We have Gigabit Fiber internet and a Wifi 6 router at home. Both my family and the house we rent behind our house use the same Wifi network because the local ISP refused to give the renters their own service and router. Everything worked for a while until we both started adding more devices to the network. Apart from the obvious security concerns, the network is starting to get crowded with multiple devices and it's also getting confusing to know what is what. Since both homes have an HP router, a Roku TV, and a bunch of other things it's happened multiple times where one person sends or starts casting things to the other's house and vice versa. And since I'm the IT member of the house, my family has asked me to "separate the wi-fi so our stuff and theirs doesn't mix together". I am very comfortable with PC hardware however I am a complete noob when it comes to network hardware.

Basically, I'm trying to setup two separate Wi-fi networks and have them share the same internet connection on our property. I tried switching the renters to the guest wifi however that doesn't allow for devices to connect to each other (which would be mainly casting to TV, sharing files over network, and printing). I was planning on just connecting an ethernet switch to two routers and just wiring it to the other house. However, someone pointed out to me that since my ISP only provides one IP address that only one router would get internet and the other wouldn't. They said that I either needed to make a setup that supports "multiple IP subnets" or "support for multiple VLANs". I asked for suggestions for devices or setups, but the person only said that most "prosumer and business routers support them". That's basically where I'm at.

Does anyone have any product recommendations or suggestions to make this work? I'd like to get some help from people who know more about this before I end up spending too much money on the wrong hardware. Thank you and have a great day.

If you don’t mind learning networking, I’d look into a more prosumer solution that supports vlans. UNIDO’s dream machine, or build your own/buy a pfsense solution. Those would be your firewall/router.

From there you would need access points which support vlans, and then you can have multiple different SSID’s, with totally different subnets, and now allow communication between them. This would wall you two off completely.

LOTS of YouTube videos on this subject, but you would need to go down a bit of a learning journey or you have never done anything like this before. But it’s really not difficult, and it’s not wildly expensive either. Can build a pfsense firewall with literally any old PC since about 2010, and UniFi AP’s are 100 bucks each, and you probably only “need” 1, but I’d get 2 for better coverage.

TheGreatestGazoo · June 8, 2023

If you have a couple of extra or old wifi routers you can use the Steve Gibson "3 dumb routers" method. You just have to configure the DHCP on each of them to use a different IP address pool. It was on a 2016 episode of Security Now so just Google that and watch the episode to get an overview. Otherwise what LIGISTX said is solid advice.

Edit - a LINK for your edification.

Genesis8935 · June 8, 2023

2 hours ago, TheGreatestGazoo said:

If you have a couple of extra or old wifi routers you can use the Steve Gibson "3 dumb routers" method. You just have to configure the DHCP on each of them to use a different IP address pool. It was on a 2016 episode of Security Now so just Google that and watch the episode to get an overview. Otherwise what LIGISTX said is solid advice.

Edit - a LINK for your edification.

9 hours ago, ThatLaloBoy said:

However, someone pointed out to me that since my ISP only provides one IP address that only one router would get internet and the other wouldn't.

Not true technically.

If the routers have the capability to disable DHCP, just do that. It'll be a pain to manage 3 DHCP servers on your network. If you go this route though, plug one router into your modem, and the rest into the LAN ports on the back of the router. On the other routers, use the LAN ports for connectivity, IIRC - Not sure if it's changed on more mainstream (for non-tech/network people or power users) consumer routers. Plugging a router into another router's WAN connection usually doesn't work on consumer routers. Though, I haven't used anything but Mikrotik since like 2014 or so.

9 hours ago, ThatLaloBoy said:

I asked for suggestions for devices or setups, but the person only said that most "prosumer and business routers support them". That's basically where I'm at.

I like and recommend Mikrotik products, tbh. It sounds like you want to set up a wireless bridge between your main house and a guest house*? If you decide to grab some Mikrotik devices, this reddit thread should be of assistance on setting up a wireless bridge.