I am trying to get the following config to work at home: Cable modem -> 8-port unmanaged switch -> 6 ethernet connections to ports within the house. One of these ports goes into a wireless router (Main floor) while the modem and switch are on a lower floor. I cannot get any port other than Port 2 to work at the same time (port 1 is the input feed from the cable modem). My challenge is that I cannot keep the wireless router downstairs as I will not get any signal strength on the floor above. What si the best possible way for me to get coverage other than using multiple WiFi Access points? I also think this config above is not secure since all the ports are not protected from the outside world. Is this a setting from my ISP or the cable modem or would this be a problem with any ISP?

Appreciate any thoughts

  • You have not provided enough information to answer your question. Of course it being an unmanaged switch, its very possible, what you want is not possible with the hardware you have. – Ramhound Sep 9 '16 at 19:59
  • Your wireless router should be directly connected to the cable modem. You cannot install a switch in between them, and expect all ports on the switch to access the Internet and/or your LAN. IOW you need to install the switch on the LAN side of the router, and not on its WAN side (unless you know what you're doing). – sawdust Sep 9 '16 at 20:12
  • In the early days cable modems were just cable modems. Then for at least a decade they were integrated with a router. Now yet again they are just cable modems, and ISPs provide a separate WiFi&Ethernet router. I guess this is a good thing, allowing one to choose their own router and/or modem. – user3015682 May 8 '20 at 0:52

You will probably need to get a second router. It does not need to be a WiFi router, but you need to have a router between your cable modem and your switch.


Most residential ISPs only offer a single IP address to their customers. When you connect a switch to your cable modem each device connected to the switch attempts to get an IP address directly from your ISP. One device will get an IP and the rest will be left withouth.

When you connect a router between the modem and the switch the router gets the 1 IP address from your ISP and creates a new network with its own private pool of IP addresses that all of your devices can connect to.

If you do add a second router you will want to disable the DHCP server on your WiFi router and plug the Ethernet cable into one of the LAN ports instead of the WAN port.

  • If you have 2 routers, do you disable DHCP for the parent or child router? – user3015682 May 8 '20 at 0:56
  • 1
    @user3015682 You would disable DHCP on the child router to let the parent assign IP addresses. If you disabled DHCP on the parent I believe the router would then be acting similar to a switch (which causes the problem described). – Matthew D. Scholefield Aug 14 '20 at 5:31

Normally ISP modem are routers. Think if you have the modem and 8-port unmanned and every one has LAN IP 192.168.x.x or 125.x.x.x. This is managed by the DHCP on the modem router and probably wifi combo your ISP install, so you are covered by the firmware of that device.

Wifi range and signal could be improved by channel management. Install some kind of wifi analyzer on your cell phone and see a free channel, once you solve the collision problem and is a big one, you can see if your modem is set up and your wifi you plan to connect to the unmanned 8-port has some join technology to work as one wifi network. I think you'll be good that way.


Your ISP will typically provide you with one public, globally routeable IP address. If you were to connect (Devices ---> Switch ---> Modem ---> ISP), your switch will attempt to assign your devices each with their own public IP address and typically would result in one of your devices receiving the ISP assigned public IP address, and the rest of your devices not having a working public IP address (IE.No Internet). If you were to add a router into the equation (Devices ---> Switch ---> Router ---> Modem ---> ISP), then once devices on your LAN attempt to access the Internet, a process called "Network Address Translation"(NAT) takes place at the router, meaning your devices' private IP addresses are automatically and seamlessly translated into that one public IP address that was assigned to you by the ISP, effectively enabling all of your devices to access the Internet.


i've used an ethernet splitter, since cat 5, 6, 7, 8 all have 8 wires and only use 4, this is possible and they cost about $10 each and you need 2, one on each end. run a short cat5 from the modem to the splitter, splitter to the wall to the upstairs into the other splitter. from that splitter into the router. then back from the router into the other port on the splitter back to the wall to downstairs, out of the other splitter into the switch. in this configuration, the router is handling almost all the load and the switch can do it's job as intended. i alos do this for multiple routers using ap mode and another switch for a workbench.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.