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Fedora 25, USB tethering not stable.

asked 2017-02-14 06:34:10 +0000

newcomer gravatar image

updated 2017-02-14 23:05:07 +0000

I am using my cellphone as a Wifi adapter but I got problem. The fedora is 25. When I turn on usb tethering from cell phone (model: LG G4), the Fedora get "USB Ethernet" and works perfectly, I can access internet normally.

I check with ifconfig, I see the cellphone interface with correct IP address like (enp0s20f0u1 is my cellphone interface)


enp0s20f0u1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet  netmask  broadcast
        inet6 fe80::942f:caff:fe19:b091  prefixlen 64  scopeid 0x20<link>
        ether 96:2f:ca:19:b0:91  txqueuelen 1000  (Ethernet)
        RX packets 46  bytes 1961 (1.9 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 205  bytes 34218 (33.4 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

After around 10 to 20 seconds, the "USB Ethernet" disappear and I got "Mobile network" from the "Network" window, and no internet anymore. I tried to configure this "Mobile" and get IP immediately, but I still don't have internet access. And I checked with ifconfig, the cellphone interface has no IP address.


enp0s20f0u1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        ether 96:2f:ca:19:b0:91  txqueuelen 1000  (Ethernet)
        RX packets 7  bytes 560 (560.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

How do I keep the USB Enthernet to get internet always working? Any clue, I appreciate.

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Do you get any related information from dmesg or journalctl -b? You should at least be able to find a log entry telling you why the kernel or NetworkManager stopped that connection. There are many possible reasons: USB connectivity problem (try a different, shorter cable); USB hardware bugs; firmware bugs; driver bugs; networking problems; …

genodeftest ( 2017-11-14 15:45:21 +0000 )edit

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answered 2017-11-14 07:43:00 +0000

aero gravatar image

updated 2017-11-14 18:43:36 +0000

genodeftest gravatar image

The solution is to disable ModemManager. It drops USB tethering.

sudo systemctl stop ModemManager.service
sudo systemctl disable ModemManager.service


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Asked: 2017-02-14 06:34:10 +0000

Seen: 352 times

Last updated: Nov 14 '17