Re: can't reach internet.

[George N. White III]

On Mon, Jun 13, 2022 at 12:34 AM home user  wrote:
> On 6/12/22 4:25 AM, George N. White III wrote:
> > On Sun, Jun 12, 2022 at 12:21 AM Tim via users
> > <[e-mail] >
> > wrote:
> > On Sat, 2022-06-11 at 19:50 -0600, home user wrote:
> >  > Multiple times over 4-5 hours I
> >  > - powered down and powered up the modem;
> >  > - reset the modem;
> >  > - disconnected and reconnected the yellow ethernet cable; and
> >  > - rebooted the work station, trying both OSs.
> >  > So I switched back and forth multiple times.  There also were
>
> other
> >  > URLs
> >  > that worked in windows-7 but not Fedora-35, but I think 3 URLs
>
> were
> >  > enough of a sample for this thread.
> >
> > Sounds like your ISP had problems.  Do they have a status page?  If
>
> so,
> > have a look, see if it lists past outages, bookmark it for next time
> > (also find its IP, now, so you can check if DNS doesn't work in the
> > future).
> >
> >
> > Randomly rebooting without gathering data is time consuming and not very
> > informative.
>
> It was not random.  The rebooting was done to:
> compare windows-7 and Fedora-35 in hopes of determining whether the
>
> problem was in Fedora-35, the modem, or "out there".
> see if something done to the modem helped.
>
> I did what I knew to do, though I recognize that my knowledge on these
> things is poor.

You will find it well worth the effort to learn some basics of network
troubleshooting:
A beginner's guide to network troubleshooting in Linux | Enable Sysadmin
(redhat.com)
https://www.redhat.com/sysadmin/beginners-guide-network-troubleshooting-linux
> > Many ISP's provide a support site that offers a speed test and in some
> > cases even include information about current status of their service.  A
> > speed
> > test can tell you if the problems you see are local or in your ISP's
> > access to
> > the wider internet.  There are also sites like downdector that collect
> > problem
> > reports and provide graphs of the numbers of reports over time.  Those
> > peaks
> > often coincide with times when I encountered problems, so can help to
> > confirm
> > that a problem wasn't something on my end.
>
> The only speed test I've ever seen seemed very "snoopy" and intrusive
> the last time I accessed it.  That was some time ago, I don't recall
> when.  I do recall Firefox and/or NoScript not liking the site.  I've
> never seen any hint of a speed test being offered by my ISP
> (comcast/xfinity), though I log into that company's site at least once
> per month.  Status site for comcast: see my reply to Tim.  What if I
> can't access comcast's/xfinity's site?

If you can't connect to your ISP's site you should call their support line
and be prepared to wait in a queue with all the others having problems
(I connect my phone to the charge and put in speaker mode so i can
do other stuff while I wait).

"Speed tests" are a popular way bad actors get victims to sites that try
to extract money.   Using your ISP's test should be as safe as anything
from your ISP.  ShieldsUP! https://www.grc.com/ is a reputable site that
you can use to scan your system for internet accessible ports.
> I could not access downdetector Saturday morning.

That is what I see when I'm having problems, but once service is
restored I can usually see the spike in reports around the time I had
a problem, which means I don't pester admins at the remote site I
couldn't reach.
> > During periods of high demand (Superbowl, public hearings by US Congress)
> > the internet may fall back to less optimal routing.  Your zoom issues
> > could be
> > due to "rate limiting" by your ISP, generally imposed during periods
>
> where
> > customer aggregate demand exceeds capacity.
>
> My zoom issues occur after the zoom meeting is done and I've left
> (disconnected from) the zoom site in Firefox, not during the meeting.  I
> have not tried any diagnosis.

Compare "ss -tl" results before, during, and after a zoom session.
> > You appear to be using a wired connection, but if you have wifi you
>
> should
> > check that only "known to you" devices are connecting.  Your router
>
> should
> > list connected devices by their MAC address, so you may want to collect
>
> the
> > MAC addresses of "known to you" devices and turn off MAC address
> > randomizaton
> > for portable devices when connected to your home wifi.
>
> I'm using a wired connection only.
> No wifi.
> No router.

Are you running internet facing services (web page, ssh, etc.)?  To list
active tcp connections and listening ports, use "ss -tl".
"ShieldsUp!!": https://www.grc.com/ is a reputable site that will tell you
which ports are open to the internet.