Do you have an old router? So you can use it as if it were a switch

Why use a router as a switch?

Generally, the routers that the operators provide us or those that we buy from the manufacturers have only four Ethernet ports, they are usually of the Gigabit Ethernet type, so we can achieve a speed of up to 1000 Mbps in download and upload, ideal for really transferring data. fast at the network level. If the four Ethernet ports are not enough for you, you can always buy a switch for about €20 to expand the number of wired ports, however, you can also choose to use the old router that you have in a drawer again, to get more ports without having to spend money on new network equipment.

All homes in Spain from the year 2011 have Ethernet network cabling in all the rooms, so these four Ethernet ports available on the router will be very short, as soon as we have a couple of bedrooms we will be really short on ports , because we will have network sockets in the two bedrooms, in the kitchen and in the living room, and generally in the living room there are two network sockets, so we will be wasting the Ethernet network sockets in our home. In the event that you do not have a new home and you have wired the house yourself, or you are simply going to connect several pieces of equipment via cable in your office, such as a couple of computers, the printer and the NAS server, we will have already occupied all the wired ports available.

Using a router as a switch is not ideal, because we have to make certain configurations for everything to work properly, in addition, the switch has some strong points compared to a router that we use as a switch:

  • The switch is generally smaller in size, and has 5 or 8 Gigabit Ethernet ports.
  • It does not have WiFi, so we will not have to deactivate it.
  • No configuration is required on an unmanaged switch, we simply plug it in and that’s it.
  • If the switch has IGMP Snooping, we will not have problems with the Multicast traffic of the IPTV that we have. With the router in switch mode we could have problems of saturation of the entire network.

Once we see the strengths of a real switch compared to an old router configured as a switch, if you have decided to use this last option, we are going to help you configure it properly.

Configure the old router as a switch

To configure the old router as a switch, we must make certain configurations so that everything works correctly. It is not as easy to use as an unmanaged switch that is totally Plug&Play, but we only have to carry out a total of three actions that we explain below. Before starting with the different configurations, you must access the configuration interface via the router’s web, for this we must know the IP address of the default gateway.

To know the default gateway, we can open a command prompt and put the command “ipconfig”. In the network card that we are using we will see “default gateway”:

Once we have this IP address, we must open a web browser and enter: and enter the router administration website. Now we must access with the administration credentials, they are generally “admin/admin”, “1234/1234” or “admin/1234” or similar credentials. It would be recommended that, if you do not access with these users and passwords, search Google for the default password of the router you have.

Before connecting the old router with the new one, you must connect directly to the old router to make all these configurations that we are going to indicate.

Change the IP of the old router

The first thing we need to do is change the LAN IP address of the old router. Generally the LAN IP address of the routers is, so the old router and new router will have IP address conflict when we connect them with each other. For this reason, it is very important that the old router has an IP address within the subnet of the new router, but that this IP address is outside the DHCP server of the new router, otherwise we could have an IP address conflict.

If the new router is configured as follows:

  • LAN IP:
  • DHCP server range: to

We can configure the IP address of the old router within the subnet but outside the DHCP range, for example, we can put the IP address without problems. In the event that our DHCP server starts from the IP, we change the configuration so that it starts from, and we configure the old router statically at this IP

Disable DHCP server

Is completely mandatory to disable the DHCP server of the old router, because the main router that we are using will be the one that acts as the main DHCP server. By deactivating it from the old router, even if we physically connect via cable or WiFi to the old router, the DHCP server of the new router will assign us a private IP address dynamically and automatically.

If you don’t disable the DHCP server of the old router, you will run into connectivity problems, especially if we are on different subnets, because the client will get the IP address from the faster DHCP server, which may not match the one we want. For this reason, it is essential to disable the DHCP of the old router so as not to have any connectivity problems.

Turn off Wi-Fi if you don’t need it

If our current main router has WiFi 5 or WiFi 6, but the old router only has WiFi 4 or earlier because it is many years old, then the best thing you can do is disable the WiFi network of this old router, because with this you will gain the following:

  • You connect to the main router and you will have higher speed.
  • The different devices connected to the old router will not stay if you move, because the old routers do not have WiFi roaming support.

If your router is relatively current, you will be able to leave the WiFi network activated, but making certain changes so that the network works perfectly:

  • WiFi network name or SSID: put exactly the same name of the WiFi network of the main router.
  • Authentication Type: Set the same as the main router.
  • Password: put the same as the one of the main router.

Change network name on the Movistar HGU router

By having the WiFi network exactly the same as the main router, the WiFi clients will be able to connect to both WiFi networks easily and quickly, without having to change networks with all that this entails. Also, depending on the device, we can have some WiFi roaming between the two routers, so that we have the best possible user experience by always having maximum coverage. Depending on the model of router you have, the graphical user interface will be different, but in all routers we always have similar menus.

Connecting the network cables

Once we have changed the IP, deactivated the DHCP server of the old router, and configured the WiFi network if we want, we must connect the cables.

To correctly connect the new router to the old one, we must take an Ethernet network cable, and connect one end to any LAN port of the new router, and to any LAN port of the old router. It doesn’t matter which port number you choose, the important thing is that we are on the LAN in both cases. If the old router turns out to be a neutral router, it will also have a WAN Internet port, but where we must place the network cable is in any of the router’s LAN ports.

By connecting a cable for interconnection, we will logically lose one LAN port on the main router and one on the old router, but we will gain a total of three more ports on the network by reusing the old router.

Check operation

Once we have all the configuration ready and also the connection of the network cabling, we can check if everything works correctly. To check it, just connect a computer via cable to the old router, and check if we have an Internet connection. If we have done everything correctly we should have an Internet connection, and we will also have communication with the home local network.

In the event that you have chosen to have the WiFi wireless network enabled, in this case you can also connect via WiFi with a laptop, smartphone or tablet, you should have communication with the Internet and with the rest of the equipment on the local network.

As you have seen, reusing our old router is a really simple process, but we must take several aspects into account: change the LAN IP, disable the DHCP server, and leave the WiFi wireless network enabled or not. Once the whole process is done, we can browse the Internet and access the local network easily and quickly.

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