[Tutorial] How to share an Ethernet internet to a wireless hotspot

Mecha Comet
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Ethernet to Wireless Hotspot

Hey everyone! Here’s a quick tutorial on how to share an Ethernet internet connection over a wireless hotspot. This allows other devices to access the internet via the wireless hotspot created on Mecha Comet.

Preview

Prerequisites

  • Ensure nmcli and nftables are installed on Mecha Comet.

  • You need sudo privileges to execute the commands.

  • Replace wlan0 and end0 with your actual Wireless interface and outbound network interface names.

  • Ensure mecha comet is connected to the Ethernet network.

Steps to Set Up the Hotspot

1. Create a Wireless Hotspot

Run the following command:


sudo nmcli device wifi hotspot ifname <wireless-interface> con-name <connection-name> ssid <ssid-name> password "<password>"

Replace the placeholders:

  • <wireless-interface>: Your Wireless interface name (e.g., wlan0).

  • <connection-name>: Desired connection name (e.g., comet-hotspot).

  • <ssid-name>: Desired hotspot name (e.g., CometHotspot).

  • <password>: Desired password for the hotspot.

Example:


sudo nmcli device wifi hotspot ifname wlan0 con-name comet-hotspot ssid CometHotspot password "mechacomet"

  • ifname wlan0: Specifies the Wireless interface.

  • con-name comet-hotspot: Sets the connection name to comet-hotspot.

  • ssid CometHotspot: Sets the SSID of the hotspot to CometHotspot.

  • password “mechacomet”: Sets the password to mechacomet.

2. Configure IPv4 Method to Shared

Modify the hotspot connection to use a shared IPv4 method:


sudo nmcli connection modify <connection-name> ipv4.method shared

Example:


sudo nmcli connection modify "comet-hotspot" ipv4.method shared

3. Bring Up the Hotspot Connection

Activate the hotspot:


sudo nmcli connection up <connection-name>

Example:


sudo nmcli connection up "comet-hotspot"

4. Configure NAT with nftables

4.1 Create a NAT Table

sudo nft add table ip nat
4.2 Add a NAT Chain

sudo nft add chain ip nat POSTROUTING { type nat hook postrouting priority 100 \; }
4.3 Add a Masquerade Rule

Add a masquerade rule for outgoing traffic through the outbound interface:


sudo nft add rule ip nat POSTROUTING oif "end0" masquerade
  • Replace end0 with your outbound network interface name.

Verification

Check the Hotspot Status


nmcli device status

Verify nftables Rules


sudo nft list table ip nat

Notes

  • Replace interface names (wlan0, end0) as needed for your setup.

  • This setup assumes the Mecha Comet’s outbound interface is end0. Adjust accordingly.

Troubleshooting

  • If the hotspot fails to start, ensure the Wireless adapter is not connected to another network.

  • Verify that nftables is enabled and properly configured.

By following these steps, you should now have a functioning Wireless hotspot with NAT configured. :tada: