Ethernet dropping out intermittently

[xedni]

My Ethernet connection has never dropped out until I did a clean install of Buster yesterday. Now it does, from time to time. I need to unplug the USB connected modem and plug it back in to reconnect. Could someone please suggest a way to troubleshoot the issue? Non-free firmware did not install from USB thumb drive, during installation, but I gather that this is just an issue in regard to Wi-Fi. Or is it?

[p.H]

What do you mean exactly by "drop out" ?
What does the USB modem have to do with ethernet ?
What ethernet controller model is it ?
Some ethernet controllers require firmwares for optimal operation.

[xedni]

What do you mean exactly by "drop out" ?
What does the USB modem have to do with ethernet ?
What ethernet controller model is it ?
Some ethernet controllers require firmwares for optimal operation.

By drop out, I mean that the USB Ethernet Connection indicator in the panel disappears and I lose Internet connectivity. To get it back, I have to unplug my modem and plug it back in.

Ethernet controller: Intel Corporation 82577LM Gigabit Network Connection (rev 06)

[Head_on_a_Stick]

Not quite the same device but maybe related: https://bugzilla.kernel.org/show_bug.cgi?id=205047

So try

Code: Select all

# ethtool -K $interface tso off

Replace $interface with the actual name of the interface (use the 'ip link' command to find that).

If it doesn't help then please post the systemd journal contents during a dropout.

[xedni]

Not quite the same device but maybe related: https://bugzilla.kernel.org/show_bug.cgi?id=205047

So try

Code: Select all

# ethtool -K $interface tso off

Replace $interface with the actual name of the interface (use the 'ip link' command to find that).

If it doesn't help then please post the systemd journal contents during a dropout.

Thanks for helping and sorry for the noob question, but I can't decipher the output of ip link in order to find the actual name of the interface. Here it is:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp0s25: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000
link/ether f0f1:3a:74:45 brd ff:ff:ff:ff:ff:ff
4: wlp2s0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
link/ether 46:58:2f:6b:d6:df brd ff:ff:ff:ff:ff:ff
34: enx0c5b8f279a64: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN mode DEFAULT group default qlen 1000
link/ether 0c:5b:8f:27:9a:64 brd ff:ff:ff:ff:ff:ff

[Head_on_a_Stick]

Code: Select all

34: enx0c5b8f279a64: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN mode DEFAULT group default qlen 1000
    link/ether 0c:5b:8f:27:9a:64 brd ff:ff:ff:ff:ff:ff

^ That's the USB interface ("enx0c5b8f279a64").

[xedni]

Code: Select all

34: enx0c5b8f279a64: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN mode DEFAULT group default qlen 1000
    link/ether 0c:5b:8f:27:9a:64 brd ff:ff:ff:ff:ff:ff

^ That's the USB interface ("enx0c5b8f279a64").

Thank you.

The output of ethtool -K enx0c5b8f279a64 tso off is:

Cannot change tcp-segmentation-offload

[Head_on_a_Stick]

Ah well, it was worth a try. Hopefully p.H will be along soon to explain why my suggestion was stupid

[xedni]

Ah well, it was worth a try. Hopefully p.H will be along soon to explain why my suggestion was stupid

I appreciate the help, in any case. Thank you.

[p.H]

Sorry but I am failing to understand which interface this is about and how it is related to a USB modem you mentionned earlier (not ethernet controller). You mentionned Intel Corporation 82577LM but AFAIK this is a PCI ethernet controller, not USB.