Can I Use Router As A Switch? | Make Extra LAN Ports

You’ve got a spare router in a drawer. Your desk has one Ethernet jack. Your TV, console, PC, and NAS all want a cable. So you look at that old box and think: can it work like a switch?

Most of the time, yes. A typical home router already has a small Ethernet switch chip inside. The trick is using the router’s LAN ports the right way and turning off the parts that cause network headaches.

This guide shows when it works, when it turns messy, and how to set it up so it behaves like a plain wired switch. You’ll also see the tradeoffs, since a real switch is still the cleanest choice in a few cases.

What A Router And A Switch Do On A Home Network

A switch is the “many ports, one network” device. Plug several wired devices in, and it forwards traffic inside the same local network. It doesn’t hand out internet access by itself. It just moves frames between ports.

A router is the “two networks” device. It connects your home network to another network (your ISP). It also tends to run services like DHCP (handing out IP addresses), NAT (sharing one public IP), and a firewall.

Here’s why this matters: when you reuse a router as a switch, you want the switching part, not the routing part. If you leave routing features active, you can end up with double NAT, two DHCP servers fighting, or a second network that breaks device discovery.

If you want a quick sanity check on the difference in plain terms, Cisco’s explainers on what a network switch is and what a router is line up well with how home gear behaves.

When A Router Can Act Like A Switch

Reusing a router works best in a simple wired expansion scenario:

• You already have one main router that connects to the modem and runs your network.
• You want extra Ethernet ports in another room or at a desk.
• You want all devices to stay on the same subnet so casting, printer discovery, local streaming, and file shares behave normally.

In that setup, the old router becomes a “port multiplier.” You connect one cable from your main router (or main switch) to the old router’s LAN side. Then you plug your devices into the old router’s LAN ports.

It can also be fine if you’re using the old router as a wired access point at the same time. The wired switching still works; you just need to configure Wi-Fi settings with care so it doesn’t compete with your main router’s wireless in annoying ways.

When It’s The Wrong Tool

There are cases where a router-as-switch setup turns into a time sink.

When You Need More Than Basic Gigabit

If your devices and cabling can run faster than 1 GbE (2.5 GbE, 10 GbE), most older routers will cap you at 1 GbE. Many cheap multi-gig switches exist now, and the price gap is often smaller than you’d expect.

When You Need VLANs Or Managed Features

Some routers can do VLAN tagging, but using them as a proper managed switch is rarely smooth. If you want per-port VLANs, QoS by port, LACP, or PoE, buy a managed switch built for that job.

When You Can’t Control DHCP

If your old router doesn’t let you disable DHCP, it’s risky to place it on the same network as your main router. Two DHCP servers can hand out conflicting IP settings, and the breakage can look random.

When You Only Have One Usable LAN Port

Some ISP gateways have limited LAN ports, and you might be tempted to chain routers in odd ways. Chaining is fine with switches. With routers, it’s easy to create a second subnet by accident and then wonder why smart home devices can’t see each other.

Can I Use Router As A Switch? In A Wired-Only Setup

Yes, you can, as long as you treat it like a LAN device and keep it from trying to be the router.

The simple rule: connect your uplink cable to a LAN port on the old router, not the WAN/Internet port. The WAN port is designed to face “another network.” Using it tends to create a separate subnet and triggers NAT or firewall behavior on many models.

Next, stop the old router from handing out IP addresses. Your main router should be the only DHCP server on the network.

After that, give the old router a fixed management IP address on your main network so you can still log into it later. Pick an address outside your DHCP pool so it won’t be handed to another device.

Once that’s done, the old router’s LAN ports behave like a basic switch. Devices plugged into it should get IP addresses from your main router and talk to everything else normally.

Step-By-Step Setup That Usually Works

Router menus differ, but the core steps stay the same. This approach works for most consumer routers from ASUS, TP-Link, Netgear, Linksys, and similar brands.

Step 1: Reset Or Start From A Clean Config

If the router has been used in odd ways, a factory reset can save time. After the reset, connect a laptop to a LAN port on the old router, then log into its admin page.

Step 2: Set A Static Management IP On Your Main Subnet

Check your main router’s LAN IP. Many are 192.168.0.1 or 192.168.1.1. If your main router is 192.168.1.1, then your subnet is likely 192.168.1.x.

Pick a free address such as 192.168.1.2 or 192.168.1.10, then set that as the old router’s LAN IP. Also set its subnet mask to match your main router (often 255.255.255.0).

Write that IP down. It’s how you’ll manage the old router later.

Step 3: Turn Off DHCP On The Old Router

Find DHCP Server settings and disable them. If you skip this, you risk two devices issuing addresses, and that can break your network in ways that come and go.

Step 4: Disable Router-Only Features You Don’t Need

Turn off features that assume the device is your edge router, such as:

• UPnP on the old router
• Firewall features tied to WAN mode
• Parental controls that intercept DNS or traffic
• Guest network modes that create isolation rules

If the router has an “Access Point mode,” that’s often the easiest choice. AP mode usually disables NAT and DHCP automatically and treats the device as a LAN extension.

Step 5: Cable It LAN-To-LAN

Run an Ethernet cable from your main router (or main switch) to a LAN port on the old router. Then plug your wired devices into the remaining LAN ports on the old router.

Step 6: Verify From A Client Device

On a laptop plugged into the old router’s LAN port, check that:

• You get an IP address in the same range as devices on the main router.
• Your default gateway is the main router’s IP, not the old router’s.
• You can reach the internet and also reach local devices (printers, NAS, casting targets).

Common Wiring And Settings Mistakes

Most failures come from a few repeat patterns. Fixing them usually takes minutes once you know where to look.

Using The WAN Port Out Of Habit

Plugging the uplink into the WAN port often creates a second network. Some routers call it “Internet,” “WAN,” or “DSL.” Avoid it for switch-like use.

Leaving DHCP Enabled

Two DHCP servers can both hand out valid-looking settings. One might point clients to the wrong gateway or DNS. Devices may work for a while, then fail after a lease renews.

Picking A Management IP Inside The DHCP Pool

If your main router hands out addresses from 192.168.1.2 to 192.168.1.200, and you set the old router to 192.168.1.50, you’ve created an IP collision risk. Put the management IP outside the pool, or reserve it on the main router.

Subnet Mismatch

If the main router is 192.168.0.1 and the old router is set to 192.168.1.1, you’re splitting your LAN. Devices can end up isolated from each other, even if the internet still works.

Compatibility Checklist For Using A Router As A Switch

Before you invest time, check these basics. It helps you predict whether the setup will stay stable.

Check	What To Look For	Why It Matters
LAN port count	At least 3 free LAN ports after the uplink	One LAN port becomes the uplink to your main network
DHCP toggle	A clear option to disable DHCP server	Prevents two devices issuing IP settings
Access Point mode	A built-in AP mode or bridge mode	Simplifies setup by disabling routing features
Gigabit ports	Ports labeled 10/100/1000	Avoids a 100 Mbps cap on modern connections
Good admin access	Local web UI reachable after changes	You’ll want to adjust settings later without resets
Stable firmware	No reboot loops, no random freezes	A flaky router makes the whole segment unreliable
Physical placement	Cool, ventilated spot near your devices	Heat and cramped spaces can cause dropouts
Power draw	Acceptable idle power for always-on use	Old routers can waste more power than a small switch

Performance And Limits You Should Expect

Even when the setup works, it’s still a repurposed device. Knowing the limits keeps expectations sane.

LAN Switching Speed Is Usually Fine

On most consumer routers, LAN-to-LAN traffic goes through an internal switch chip. That means file copies between two wired devices can hit near-gigabit speeds if the ports are gigabit and the cables are decent.

Where it can slow down is when traffic passes through routing or firewall code. That’s another reason to avoid WAN mode when you’re trying to use it like a switch.

Latency Is Rarely A Problem On LAN Ports

For gaming and streaming, a basic LAN switch function adds tiny delay. Your bigger risks are bad cables, overloaded Wi-Fi, or bufferbloat on the internet uplink.

Energy Use Can Be Higher Than A Small Switch

A purpose-built 5-port gigabit switch is often very low power. An old router can draw more since it’s running a full CPU, radios, and extra services even when you disable some features. If it’s going to run 24/7, the power cost can make a cheap switch feel worth it.

Using A Router As A Switch With LAN Ports Only

If you want the simplest mental model, treat the old router as a box with a few LAN sockets. Nothing more.

That means:

• Do not use its WAN port for the uplink.
• Do not let it hand out IP addresses.
• Do not let it become the default gateway for clients.
• Do not create a second Wi-Fi network unless you really want one.

Once it’s set up this way, you can forget it’s a router. It’s just a small wired expansion point.

What If I Want Wi-Fi Too?

You can still use it for extra wired ports and Wi-Fi at the same time. That’s basically “access point + switch.” Many routers even offer an explicit Access Point mode, which is built for this.

SSID Choices

If you want one seamless network name, you can set the same SSID and password as your main Wi-Fi. Roaming between access points is device-driven; some devices roam smoothly, some cling to the first signal they saw.

If you want more control, give the old router a distinct SSID like “Home-Office.” That makes it obvious which access point you’re on when you troubleshoot.

Channel Choices

Pick channels that don’t overlap with your main Wi-Fi. On 2.4 GHz, that often means 1, 6, or 11, spaced apart. On 5 GHz, pick a channel range that isn’t crowded in your area. Auto can work, but manual settings reduce surprises if you have multiple access points close together.

Second Table: Quick Fix Map For Common Problems

If something feels off after setup, this map gets you back to a stable state fast.

Symptom	Likely Cause	Fix
Devices get internet, but can’t see printer/NAS	Uplink plugged into WAN port, creating a second subnet	Move the uplink cable to a LAN port and reboot clients
Random disconnects or “no internet” popups	Two DHCP servers handing out leases	Disable DHCP on the old router, renew client leases
Can’t reach the old router’s admin page	Management IP unknown or on a different subnet	Set a known static IP, or reset and reconfigure
One device works, another won’t connect	IP address conflict	Move management IP outside the DHCP pool, reboot affected devices
Wired speed stuck around 95 Mbps	100 Mbps ports, bad cable, or forced link speed	Swap cable, confirm gigabit ports, check NIC settings
Streaming stutters on one room’s devices	Bad cable run or overheating router	Test with a short cable, relocate for airflow

Should You Buy A Real Switch Instead?

Sometimes the clean answer is still a switch. Here’s when spending a little money saves a lot of friction:

• You want a tiny device with very low power draw.
• You want multi-gig speeds.
• You need PoE for cameras or access points.
• You want managed features like VLANs in a tidy interface.
• Your old router is unstable, runs hot, or doesn’t let you disable DHCP.

If none of those apply and you already own the router, reusing it can be a solid stopgap. It’s also a handy way to validate how many ports you really need before buying hardware.

Final Checks Before You Walk Away

Do these quick checks once, then you can treat the setup as “set and forget.”

• Confirm the uplink cable is LAN-to-LAN.
• Confirm DHCP is disabled on the old router.
• Confirm client devices show the main router as default gateway.
• Confirm you can still log into the old router using its static management IP.
• Label the old router’s power brick and management IP so you don’t have to guess later.

With those boxes checked, using a router as a switch is usually steady. Your wired devices get the ports they need, and your main router keeps full control of the network.