Network connections have gone erratic

[Bret Busby]

On 22/11/23 23:54, Bret Busby wrote:
> On 22/11/23 23:36, Jeffrey Walton wrote:
>> On Wed, Nov 22, 2023 at 10:28 AM Bret Busby <bret at busby.net> wrote:
>>>
>>> On one of my computers running Linux Mint Mate 21.2, I, yesterday or the
>>> day before, did a system update that included an update of avahi, which
>>> is apparently, a networking utility.
>>>
>>> Afterward, the computer, which I have had connected by wifi to a wifi
>>> modem, and, by USB tethering, to my cellphone for Internet access, both
>>> devices using 4G cellphone networks with different carriers, to access
>>> the Internet, with the USB tethering involving "hot plugging" (?), can
>>> no longer use the USB tethering, which, whilst I set the USB tethering
>>> to "On", on the cellphone, is automatically severed, with no data shown
>>> as being transferred, and, the NetworkManager Applet shows the wifi
>>> connection to the wifi modem, to be in an endless loop of dropping out
>>> and reconnecting.
>>>
>>> I can send and receive data, but, it is erratic.
>>>
>>> I do not know whether the networking connections failing, is due to the
>>> avahi upgrade, or just coincides with the timing, but, it is worrying.
>>>
>>> Prior to the avahi update, I had not encountered this problem, and, the
>>> networking connections had been stable.
>>>
>>> I had performed an orderly shutdown and reboot, to find whether that
>>> might fix this, but, it did not fix the problem.
>>>
>>> How do I find what is causing this, and, how do I fix it?
>>
>> I _think_ I encountered a similar issue about a year or so ago. When
>> my Pixel was tethered to my Desktop, the desktop would try to use the
>> network connection from the phone rather than wired ethernet. The
>> pixel used wifi, and wifi was outside my internal wired network. So my
>> desktop (using the Pixel) could no longer talk to other hosts on my
>> internal (wired ethernet) network.
>>
>> I filed a bug report about it. I don't think it was fixed. I
>> eventually installed a new distro for this machine. The problem went
>> away. I _think_ changing network costs or priorities could have fixed
>> the issue.
>>
>> I don't think Avahi has anything to do with it. Avahi is just mDNS.
>>
>> Jeff
>>
> 
> Prior to the update, the computer would use the wifi connection to the 
> modem, if the cellphone was not connected, and, when the cellphone was 
> connected and USB tethering switched on, the computer would switch to 
> using that, which was shown as a wired (like Ethernet) connection.
> 
> The Mate Netspeed applet, whilst, when the cellphone is not connected, 
> shows zero data transmission speeds (but, shows as being connected to 
> the wifi modem), before this problem incident, would show the data 
> transmission rates for the USB tethered cellphone, showing that as a 
> wired connection.
> 
> The wifi adaptor on the computer, is a USB wifi dongle, which, I 
> believe, is why (a shortcoming, I believe, in the software involved in 
> the applet) the MATE Netspeed applet does not show data transmission 
> speeds as non-zero, for the wifi adaptor. On my other computers, running 
> the identical operating system, the MATE Netspeed applet correctly shows 
>   the data transmission speeds; the difference being that, on the other 
> computers, the wifi devices are integral parts of the respective 
> computers, causing me to believe that the failure to show the data 
> transmission speeds for the USB wifi dongle, is a shortcoming of the 
> applet, in that it does not properly deal with the USB wifi dongle.
> 
> But, the MATE Netspeed applet correctly displays the data transmission 
> speeds for the USB tethered cellphone connection, which is also, a USB 
> connected device...
> 
> ....
> Bret Busby
> Armadale
> Western Australia
> (UTC+0800)
> .................
> 
> 

NetworkManager Applet - version 1.24.0

MATE Netspeed applet - version 1.26.0

....
Bret Busby
Armadale
Western Australia
(UTC+0800)
.................