[Howto] Share Ethernet Via Wifi With NetworkManager In KDE
Dominica Peche
The basic situation is rather common: you have one single network connection, and want to share it to other people or devices via wifi. If you want to do that manually you have to set up the wifi network on your own, including encryption, need to bring up a dhcp server, configure the routing and NATing, and so on. That can take quite some time, and is nothing you want to do during some precious training hours.
Thus I simply tried to bring up a shared wifi via the NetworkManager applet in KDE:
After providing a SSID name and configuring some security credentials the process was already done, and I was notified that the network was set up and ready. It was also shown in the plasma applet besides the ethernet connection:
This creates a subnet at 10.42.0.1 and uses dhcp. I need to share without dhcp and use the same network as that connected to the internet, using the dhcp from the upstream router.
My system is Gentoo 64bit, with KDE. I want to share my wifi connection with other devices. I am able to do this with Windows 7, so I think my device is able to setup an AP. And I find out that in KDE, the NetworkManager can set up a shared wifi connection.
There are many tutorials out there explaining how to achieve this, with different degrees of difficulty. NetworkManager hides all this complexity and provides a shared mode that makes this configuration quick and convenient.
10.42.0.1/24 is the default address set by NetworkManager for a device in shared mode. Addresses in this range are also distributed via DHCP to other computers. If the range conflicts with other private networks in your environment, change it by modifying the ipv4.addresses property:
Will this command support simultaneous AP+STA? In other words, if I am already connected to the Internet via WiFi, will this command create an AP which will allow me to share my WiFi Internet connection with other devices?
To remotely access your device from your PC, first you need to get your PC and your device on the same local network. If you can plug your Jetson TK1 board directly into a wired ethernet router from the onboard ethernet port or plug a Wifi USB dongle / PCIe card, then this is all you need to do. The device will get a new IP address from the DHCP server in your router, and thus your PC should be able to access your device within 30 seconds or so, and the device should have access to both the PC and the internet such as to download extra software.
With KDE Plasma 5, you can easily share your internet connection from LAN/USB tethering/USB modem as WLAN hotspot to another computers. Plasma Desktop gives a good GUI to set it up quickly without Terminal. You even don't need hostapd to do this. This tutorial is not limited to Ubuntu, so any GNU/Linux distro with Plasma 5 can do it. Here I use my USB tethering as source, a first laptop as hotspot (Neon & Plasma 5.9), and a second laptop as client. If you have similar devices, you can do this at home.
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Requirements
In this tutorial, I use these stuffs:
- A smartphone capable to do USB tethering
- A working internet access in my smartphone
- Two laptops, one as hotspot and one as client
- Neon OS with KDE Plasma 5.9 in hotspot laptop
- Ubuntu MATE in client laptop
1. Enable The Internet Source
Connect your smartphone to the KDE laptop > enable its USB tethering > make sure the KDE laptop connected to the internet.
2. Create WLAN Hotspot
Open KDE System Settings > Networks > Connections > press "+" (PLUS) button > select "WIFI (Shared)" > press "Create" > name the "Connection name:" e.g. WLAN Hotspot (seen on hotspot laptop) > name the "SSID" e.g. my_hotspot (seen on client laptop) > OK.
3. Hotspot Laptop Connects to WLAN Hotspot
In KDE Plasma, click network icon on panel > connect to "WLAN Hotspot" (the connection name you have determined) > leave the "my_hotspot" (the SSID you have determined) untouched.
4. Client Laptop Connects to WLAN Hotspot
In client laptop, for any operating system, just find out the WLAN hotspot name ("my_hotspot") and connect to it. Now you can browse the internet on the client laptop. You can also connect any other device to it.
Additional Info
For further use, you can consider these information:
- You may share your internet to any number of client laptops/computers/devices.
- You may limit user access by giving your hotspot a password.
- You can transfer files (via SFTP protocol) between computers connected via the hotspot.
- You may configure a captive portal if you want to create e.g. a paid public hotspot using Chilispot (advanced).
- And there is even a GNU/Linux distro designed to be an instant captive portal called EasyHotspot.
As long as your carrier doesn't limit how you use your data, internet connection sharing (also known as netshare) with a Linux computer is a good option. Wi-Fi tethering is one option---here's how to use USB tethering on Linux with Android and iPhone.
Want to share your phone's internet connection with a different operating system? You can connect mobile internet from an Android phone to your PC or laptop, as well as use the hotspot feature on an iPhone.
To connect to a Samba share on Linux with Dolphin, start by opening up the file manager. Then, click the location bar with the mouse and erase the text in the box with the Backspace key.
The sections within one file are considered in order of appearance, with the exception that the [connection] section is always considered last. In the example above, this order is [connection-wifi-wlan0], [connection-wlan-other], and [connection]. When checking for a default configuration value, the sections are searched until the requested value is found. In the example above, "ipv4.route-metric" for wlan0 interface is set to 50, and for all other Wi-Fi typed interfaces to 55. Also, Wi-Fi devices would have IPv6 private addresses enabled by default, but other devices would have it disabled. Note that also "wlan0" gets "ipv6.ip6-privacy=1", because although the section "[connection-wifi-wlan0]" matches the device, it does not contain that property and the search continues.
Like the per-connection settings ethernet.generate-mac-address-mask and wifi.generate-mac-address-mask, this allows to configure the generated MAC addresses during scanning. See nm-settings(5) for details.
If wifi.backend is iwd, setting this to false forces IWD's autoconnect mechanism to be disabled for this device and connections will only be initiated by NetworkManager whether commaned by a client or automatically. Leaving it true (default) stops NetworkManager from automatically initiating connections and allows IWD to use its network ranking and scanning logic to decide the best networks to autoconnect to next. Connections' autoconnect-priority, autoconnect-retries settings will be ignored. Other settings like permissions or multi-connect may interfere with IWD connection attempts.
I do that for my various defined ethernet and wifi connections.
I use it to create several kind of connection excluding tethering. Tethering connection is (or should be) created automatically when insert usb cable and activate usb tethering in phone.
Sometimes we want to have several connections at the same time, one to the ethernet (wired lan) and one other to the wireless router, with two different gateways. In this documentation i describe how to make wireless connection prior to ethernet connection in each linux OS using NetworkManager service to moderate network connections. I've tested these instruction in fedora 31 already.
Using NetworkManager and ModemManager in Linux to automatically establish a connection and configure IP details
In this FAQ we will show how to set up NetworkManager to automatically configure, establish the cellular data connection in your system.
NetworkManager and ModemManager are open source tool for Linux to manage several types of networks and interfaces such as ethernet, wifi, etc. It can also manage cellular WWAN interfaces through the ModemManager tool.
It is hosted by the Freedesktop.org community and driven by Aleksander Morgado and other contributors. please visit and for latest information, source code, API reference manuals, debugging tips, contribution, mailing list etc.
ModemManager is capable of communicating over several types of device control channels such as QMI/RMNET, MBIM, MODEM / AT command etc. But support for vendor proprietary or out-of-kernel drivers are none or very limited. Such drivers are gobinet, simcom_wwan and other drivers provided by the vendors directly.
Many Linux distributions have NetworkManager and ModemManager pre-installed or they can typically easily be installed through the systems package manager.
In Ubuntu for example apt can install it for you by command if not already installed:
apt install network-manager
Check with commands below that you have both tools installed in system and their versions.
NetworkManager -V
ModemManager -V
ModemManager (and NetworkManager) are continuously developed for better compatibility with the cellular devices, therefore it is recommend to use a recent version of the tools and in case of problem situations, evaluate the latest versions from source and check the mailing list archives for possible discussions on the problem experienced.
Keep in mind that NetworkManager and ModemManager projects are not directly developed or driven by the cellular device vendors and the compatibility with the device you aim to use can be limited. Some vendors contribute with code to make their devices fully compatible, while others don't. Many cellular devices can be set to expose standardized types of USB network interface and control channel such as MBIM interface by USB-IF or the Qualcomm proprietary interface QMI that ModemManager will try to identify, and often manage to work successfully with but there are exceptions also.
Both NetworkManager and ModemManager have command line interfaces (nmcli and mmcli respectively) where you can interact with the management tools.
Relate to the following FAQ if you want more details for using ModemManager only to configure and control the cellular device but manually establish, maintain the connection and network interface IP address details.
How-to guide: control and set up a data connection in Linux using ModemManager as connection manager?
Have ModemManager list all the cellular device it has detected. Here we use the Alcatel IK41 series with MBIM interface in this example:
mmcli --list-modems
/org/freedesktop/ModemManager1/Modem/0 [Alcatel] Mobilebroadband
General details and status of them modem can be listed with "--modem" option.
mmcli --modem=0
-----------------------------
General dbus path: /org/freedesktop/ModemManager1/Modem/0
device id: 998e478c5b14c75e16bffe6abaacabef22fb2f5b
-----------------------------
Hardware manufacturer: Alcatel
model: Mobilebroadband
firmware revision: MPSS.JO.2.0.2.c1.7-00004-9607_
carrier config: default
h/w revision: 0
supported: gsm-umts, lte
current: gsm-umts, lte
equipment id:
-----------------------------
System device: /sys/devices/pci0000:00/0000:00:14.0/usb3/3-1
drivers: option1, cdc_mbim
plugin: Generic
primary port: cdc-wdm0
ports: cdc-wdm0 (mbim), ttyUSB0 (at), ttyUSB2 (at), wwan0 (net),
ttyUSB1 (qcdm)
-----------------------------
Status lock: sim-pin
unlock retries: sim-pin (3)
state: locked
power state: on
signal quality: 0% (cached)
-----------------------------
Modes supported: allowed: 2g; preferred: none
allowed: 3g; preferred: none
allowed: 4g; preferred: none
allowed: 2g, 3g; preferred: 3g
allowed: 2g, 3g; preferred: 2g
allowed: 2g, 4g; preferred: 4g
allowed: 2g, 4g; preferred: 2g
allowed: 3g, 4g; preferred: 3g
allowed: 3g, 4g; preferred: 4g
allowed: 2g, 3g, 4g; preferred: 4g
allowed: 2g, 3g, 4g; preferred: 3g
allowed: 2g, 3g, 4g; preferred: 2g
current: allowed: 2g, 3g, 4g; preferred: 2g
-----------------------------
Bands supported: egsm, dcs, pcs, g850, utran-1, utran-8, eutran-1, eutran-3,
eutran-7, eutran-8, eutran-20, eutran-28
current: egsm, dcs, pcs, g850, utran-1, utran-8, eutran-1, eutran-3,
eutran-7, eutran-8, eutran-20, eutran-28
-----------------------------
IP supported: ipv4, ipv6, ipv4v6
-----------------------------
SIM dbus path: /org/freedesktop/ModemManager1/SIM/0
Check that the cellular device is managed by NetworkManager by not having state "unmanaged" listed for it.
nmcli device status
DEVICE TYPE STATE CONNECTION
cdc-wdm0 gsm disconnected --
enp3s0 ethernet unmanaged --
lo loopback unmanaged --
Now you should create a connection profile in NetworkManager for your specific network carrier and SIM card with the "nmcli connection add" command:
For example:
nmcli connection add type gsm ifname '*' con-name '3-sweden' apn 'data.tre.se' connection.autoconnect yes gsm.pin 0000
- type is gsm for all typical cellular connections unless it is of cdma type.
- ifname is the control interface name, in this case cdc-wdm0, wildcard can be used also to have it autoselect.
- con-name is the profile name you want to give it.
- apn is provided by your network carrier and tells the modem what attach point it should use for the data connection.
- connection.autoconnect set to yes will make NetworkManager always try to auto connect and maintain this profile connection.
- gsm.pin lets you provide a pin code for the SIM card, that NetworkManager will try to use if PIN check is enabled for SIM card.
There are several additional commands and attributes available such as username and password settings for the APNs etc. Refer to the NetworkManager help and manual pages for full details on the commands.
If successful you should receive a reply similar to this one:
Connection '3-sweden' (cad6fcbf-2cb1-4796-b7e6-67b9f9635aef) successfully added.
You can check the status now by command:
nmcli device status
DEVICE TYPE STATE CONNECTION
cdc-wdm0 gsm connected 3-sweden
enp3s0 ethernet unmanaged --
lo loopback unmanaged --
Where connected should be listed as state if the connection establishment was successful.
If the connection is not successful or you want more details about the device and connection you can check commands:
You can list the current status with command:
nmcli radio
WIFI-HW WIFI WWAN-HW WWAN
enabled enabled enabled enabled
nmcli device show cdc-wdm
GENERAL.DEVICE: cdc-wdm0
GENERAL.TYPE: gsm
GENERAL.HWADDR: (unknown)
GENERAL.MTU: 1500
GENERAL.STATE: 100 (connected)
GENERAL.CONNECTION: 3-sweden
GENERAL.CON-PATH: /org/freedesktop/NetworkManager/ActiveConnection/18
IP4.ADDRESS[1]: 2.68.73.130/30
IP4.GATEWAY: 2.68.73.129
IP4.ROUTE[1]: dst = 2.68.73.128/30, nh = 0.0.0.0, mt = 700
IP4.ROUTE[2]: dst = 0.0.0.0/0, nh = 2.68.73.129, mt = 700
IP4.DNS[1]: 80.251.201.177
IP4.DNS[2]: 80.251.201.178
IP6.ADDRESS[1]: 2a02:aa1:1017:6d11:1060:3dff:feac:e92f/64
IP6.ADDRESS[2]: 2a02:aa1:1017:6d11:6474:7254:7b72:eb09/64
IP6.GATEWAY: 2a02:aa1:1017:6d11:21e6:9049:6cfb:8ac3
IP6.ROUTE[1]: dst = ff00::/8, nh = ::, mt = 256, table=255
IP6.ROUTE[2]: dst = 2a02:aa1:1017:6d11::/64, nh = ::, mt = 700
IP6.ROUTE[3]: dst = ::/0, nh = fe80::21e6:9049:6cfb:8ac3, mt = 1024
IP6.ROUTE[4]: dst = 2a02:aa1:1017:6d11::/64, nh = ::, mt = 256
IP6.ROUTE[5]: dst = ::/0, nh = 2a02:aa1:1017:6d11:21e6:9049:6cfb:8ac3, mt = 700
IP6.DNS[1]: 2a02:aa0::55
IP6.DNS[2]: 2a02:aa0::56
nmcli connection show
NAME UUID TYPE DEVICE
3-sweden e946017f-2e9c-477b-89ad-4c31e7331d65 gsm cdc-wdm0
Ifconfig should now show the related IP address details already set to the network interface by NetworkManager:
ifconfig
wwan0: flags=4291 mtu 1500
inet 2.68.73.130 netmask 255.255.255.252 broadcast 2.68.73.131
inet6 2a02:aa1:1017:6d11:6474:7254:7b72:eb09 prefixlen 64 scopeid 0x0
inet6 2a02:aa1:1017:6d11:1060:3dff:feac:e92f prefixlen 64 scopeid 0x0
ether 12:60:3d:ac:e9:2f txqueuelen 1000 (Ethernet)
RX packets 186 bytes 10886 (10.8 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 5 bytes 480 (480.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
You can now for example test the connection over the network interface by sending ping requests.
Testing IPV4 connection:
ping -4 -I wwan0 8.8.8.8
PING 8.8.8.8 (8.8.8.8) from 2.68.73.130 wwan0: 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=118 time=55.8 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=118 time=45.4 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=118 time=42.9 ms
--- 8.8.8.8 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2003ms
rtt min/avg/max/mdev = 42.918/48.053/55.845/5.601 ms
Testing IPV6 connection: (if your cellular device, network subscription and APN supports it)
ping -6 -I wwan0 2600::
PING 2600::(2600::) from 2a02:aa1:1017:6d11:1060:3dff:feac:e92f wwan0: 56 data bytes
64 bytes from 2600::: icmp_seq=1 ttl=46 time=172 ms
64 bytes from 2600::: icmp_seq=2 ttl=46 time=171 ms
64 bytes from 2600::: icmp_seq=3 ttl=46 time=169 ms
64 bytes from 2600::: icmp_seq=4 ttl=46 time=168 ms
--- 2600:: ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3004ms
rtt min/avg/max/mdev = 167.921/170.037/172.272/1.651 ms
The connection is successful and automatic reconnect is working when testing to unplug and plug in the device again.
For additional configurations, commands and available attributes, please relate to the manual pages for NetworkManager and ModemManager.
Troubleshooting logs:
NetworkManager and ModemManager write log messages to the Linux syslog file /var/log/syslog.
In case of problems with establishing a cellular data connection, please copy the logfile after the problem have appeared and include it in a Techship technical support ticket.
In some situations more detailed debug logs are needed, these can be acquired by changing the log levels for NetworkManager and ModemManager and run them manually.
To capture debug logs, please first disable and stop the normal services:
systemctl stop NetworkManager ModemManager
systemctl disable NetworkManager ModemManager
Run them manually in background with debug level set:
/usr/sbin/ModemManager --log-level=DEBUG &> /dev/null &
/usr/sbin/NetworkManager --log-level=DEBUG &
Reproduce the cellular data connection problem.
Once completed, kill the processes:
killall -TERM NetworkManager ModemManager
Copy the relate messages in syslog to a mm-nm-sys-debug.log logfile:
grep -E 'ModemManagerNetworkManagersystemddbus-daemondhclient' /var/log/syslog > mm-nm-sys-debug.log
Activate and start the services again:
systemctl enable NetworkManager ModemManager
systemctl start NetworkManager ModemManager
Include the mm-nm-sys-debug.log in a technical support ticket at Techship.com where you describe the issue in details and include other relevant information also such as kernel version, ModemManager and NetworkManager versions, dmesg log etc.