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Is it possible to create a wireless bridge connection (br0) for any wireless nic (wlan0) using nmcli tool.?

End of the day system should have master bridge-connection(br0) that uses wlan0 nic as it's bridge-slave.

2 Answers 2

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It is possible.

If your goal is to create a WiFi Hotspot/Access Point and bridge it to your ethernet connection, you can do that using nmcli.

If your computer is connected to a router via an ethernet cable you will be able to use your computer as a WiFi hotspot, your WiFi AP clients can get their IPs directly from the router and neatly be part of the same network as the other devices.

First create your bridge connection:

nmcli connection add con-name 'My Bridge' ifname br0 type bridge ipv4.method auto ipv6.method disabled connection.autoconnect yes stp no

Now add your Ethernet card (eth0) as a slave to the bridge:

nmcli connection add con-name 'My Ethernet' ifname eth0 type bridge-slave master 'My Bridge' connection.autoconnect yes

Now create your WiFi Access Point and add it as a slave to the bridge. The syntax for the WiFi slave is a bit different:

nmcli connection add con-name 'My Hotspot' ifname wlan0 type wifi slave-type bridge master 'My Bridge' wifi.band a wifi.channel 153 wifi.mode ap wifi.ssid my-hotspot-ssid 

It will create a working hotspot without a password.

There is actually a bug under version 1.22.10 shipped with Ubuntu 20.04 that prevents using WPA2. It creates the network but clients are unable to authenticate. This is the bug report. It is reportedly fixed in version 1.30 of NetworkManager, if you have such version, you could try to go for WPA2 with wifi-security.key-mgmt wpa-psk (or maybe WPA3 with wifi-security.key-mgmt sae) and setting the password with wifi-sec.psk yourpassword.

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This is not possible.

"Note that a bridge cannot be established over Wi-Fi networks operating in Ad-Hoc or Infrastructure modes. This is due to the IEEE 802.11 standard that specifies the use of 3-address frames in Wi-Fi for the efficient use of airtime."

Source: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Networking_Guide/ch-Configure_Network_Bridging.html

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    How come this is offered by routers / access points when put in bridge mode?
    – Andreas
    Commented Mar 14, 2023 at 14:57

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