Internet Connection Sharing

The following example will describe how to share an active internet connection over a WiFi hotspot or alternatively via ethernet.

Share via WiFi

Usage

Share an existing internet connection of a wired interface eth0 using a wifi hotspot on wlan0 with the access point name MyAccessPoint.

nix shell nixpkgs#linux-wifi-hotspot
sudo create_ap wlan0 eth0 MyAccessPoint

Configuration

Persistent share an existing internet connection of a wired interface eth0 using a wifi hotspot on wlan0 with the access point name My Wifi Hotspot. The network is protected with a simple WPA2 pre-shared key 12345678.

services.create_ap = {
  enable = true;
  settings = {
    INTERNET_IFACE = "eth0";
    WIFI_IFACE = "wlan0";
    SSID = "My Wifi Hotspot";
    PASSPHRASE = "12345678";
  };
};

Share via ethernet

Share an existing internet connection of a wireless interface wlan0 to clients connected on a ethernet device eth0.

# Setup ethernet device
ip link set up eth0
ip addr add 10.0.0.1/24 dev eth0

# Enable packet forwarding
sysctl net.ipv4.ip_forward=1

# Enable NAT for leaving packets
iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE

# Start dnsmasq for DHCP
dnsmasq -d -i eth0 --dhcp-range=10.0.0.2,10.0.0.255,255.255.255.0,24h

To cleanup the configured interface run following commands

ip addr del 10.0.0.1/24 dev eth0
ip link set down eth0
iptables -t nat -D POSTROUTING -o wlan0 -j MASQUERADE