On 6/13/22 4:30 AM, George N. White III wrote:
> 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>
I gave it a first pass. For me, it seemed to be overkill; much was over
my head. But I'll give it a second-pass reading later.
> 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?
>
> "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/ <https://www.grc.com/>
> is a reputable site that
> you can use to scan your system for internet accessible ports.
Tried that this morning, from Firefox running in Fedora. It seemed to
think it was a windows box that I was testing. Otherwise, the tests
seemed to work, and claimed my workstation was clean.
> I could not access downdetector Saturday morning.
The graph is for the past 24 hours. I usually see problems from
coffee break to coffee break and evening peak times, so if I had
problems I check early the next 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.
I looked at that this morning to see if it would report on
comcast/xfinity. It did. Would have been nice if it had given me a way
of seeing back to Saturday morning, but I did not see any such
functionality.
> Compare "ss -tl" results before, during, and after a zoom session.
I'll try to remember to try that.
> 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/ <https://www.grc.com/> is a
> reputable site that will tell you
> which ports are open to the internet.
This is a "simple" home workstation: tower connected via 1 yellow
ethernet cable to one internet&voice modem. The phone is a land line.
I'm not running any internet-facing services that I know of. GRC says I
have no ports open to the internet, but it also seems to think this is a
windows box. (It is a Fedora and windows-7 dual boot system, but I was
using Fedora for the GRC tests.)
I don't think GRC cares about your OS -- it can check for "most common"
ports or all ports. Some ports were first used for Microsoft protocols, but
Linux often provides versions of Windows services.