How to make a router on raspberry pi zero 2w?

You can turn a Raspberry Pi Zero 2 W into a little Wi-Fi router pretty easily — the main trick is:

Use a USB-Ethernet adapter as WAN (internet in) and the Pi’s built-in Wi-Fi as an access point (Wi-Fi out), with NAT + DHCP in the middle.

I’ll assume you’re on Raspberry Pi OS Bookworm (the current default) and use the NetworkManager way, which is much simpler than the old hostapd + dnsmasq + iptables dance.

1. What you’ll need

Hardware

• Raspberry Pi Zero 2 W
• Good 5 V power supply
• microSD card (8 GB+)
• micro-USB OTG adapter
• USB-Ethernet adapter (this will be your WAN connection)
• Ethernet cable to your existing router/modem

Result

• eth0 (USB-Ethernet) = uplink to the internet
• wlan0 (on-board Wi-Fi) = Wi-Fi router/AP for your devices
• Pi does routing + NAT + DHCP between the two.

2. Basic OS setup

1. Flash Raspberry Pi OS Lite (Bookworm) onto the SD card using Raspberry Pi Imager.
2. In Imager’s “advanced options”, enable SSH and set Wi-Fi only if you want initial access via Wi-Fi.
3. Boot the Pi Zero 2 W.
4. Plug in the USB-Ethernet adapter, connect it to your main router. It should get an IP via DHCP automatically.
5. SSH into the Pi and update:

sudo apt update
sudo apt full-upgrade -y

Bookworm uses NetworkManager by default, so we’ll configure everything with nmcli.

3. Create the Wi-Fi router (AP) on wlan0 with NetworkManager

NetworkManager has a built-in “shared” mode: it automatically turns the interface into a NAT router + DHCP server for clients. That’s exactly what we want.

Run these commands on the Pi:

# 1) Create a Wi-Fi connection called "pi-router" in AP mode
sudo nmcli con add type wifi ifname wlan0 mode ap con-name pi-router ssid PiZeroRouter

# 2) Give it a static IP and enable shared/NAT mode
sudo nmcli con modify pi-router \
  802-11-wireless.band bg \
  ipv4.method shared \
  ipv4.address 192.168.50.1/24 \
  ipv6.method disabled

# 3) Set Wi-Fi password (WPA2)
sudo nmcli con modify pi-router wifi-sec.key-mgmt wpa-psk
sudo nmcli con modify pi-router wifi-sec.psk "VeryStrongPassword123"

# 4) Bring the AP up
sudo nmcli con up pi-router

What this does:

• Makes **wlan0 broadcast PiZeroRouter** with WPA2 password VeryStrongPassword123.
• Gives the Pi IP 192.168.50.1/24 on that Wi-Fi network.
• **ipv4.method shared** tells NetworkManager to:
• turn on IP forwarding
• enable NAT from wlan0 to the default route (which will be via eth0)
• run a small DHCP server on wlan0 so clients get addresses like 192.168.50.x.

At this point:

• Plug eth0 into your normal router.
• Connect your phone/laptop to PiZeroRouter.
• You should get an IP in 192.168.50.x and have internet via the Pi.

You can check:

ip addr show wlan0
ip route
nmcli device

and from a client:

• ping 192.168.50.1 (Pi)
• ping 8.8.8.8 (internet)
• open a web page

4. Making it persistent & checking forwarding

NetworkManager remembers connections, so after reboot it should bring pi-router up automatically.

If you want to be extra sure that IP forwarding is enabled system-wide:

grep ip_forward /etc/sysctl.conf
# If it's commented, add:
echo "net.ipv4.ip_forward=1" | sudo tee -a /etc/sysctl.conf
sudo sysctl -p

(Usually ipv4.method shared handles this for you, but it’s nice to know where it lives. )

5. What if I want Wi-Fi in → Wi-Fi out?

On the Pi Zero 2 W you only have one built-in Wi-Fi radio (wlan0). Using it as both client and AP at the same time is possible in some chipsets / modes but:

• It’s fragile,
• You can’t do true bridging of a Wi-Fi client interface,
• Best practice is to route between two different interfaces (e.g. onboard Wi-Fi as AP and a USB Wi-Fi dongle as uplink).

If you want “Wi-Fi repeater” style:

• Use onboard Wi-Fi as AP (wlan0, as above)
• Add a USB Wi-Fi dongle (wlan1) as upstream client using another nmcli connection, with ipv4.method auto.
• NetworkManager will then route/NAT from wlan0 (AP) to wlan1 (upstream).

6. Old-school alternative: hostapd + dnsmasq + iptables

If you ever want more manual control (or you disable NetworkManager), the classic method is:

1. Install:

sudo apt install hostapd dnsmasq

2. Give wlan0 a static IP (e.g. via /etc/dhcpcd.conf on older releases).

3. Configure dnsmasq as DHCP server on wlan0.

4. Configure hostapd with SSID, channel, WPA2 password, etc.

5. Enable IP forwarding and iptables MASQUERADE from wlan0 → eth0.

This is the approach in many older Raspberry Pi and Pi Zero W router tutorials.

But on Bookworm the NetworkManager method you just used is simpler and works nicely on a Zero 2 W.