Network connections have gone erratic

[Jeffrey Walton]

On Wed, Nov 22, 2023 at 10:36 AM Jeffrey Walton <noloader at gmail.com> 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.

Here's the bug report:
<https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1975549>.

> I don't think Avahi has anything to do with it. Avahi is just mDNS.

Jeff