Question Trying to prove whether intermittent connection issues are modem or Comcast Xfinity

[todafoa]

This is an old repetitive story but it's happening again now at new place after 6 months of almost flawless internet connection and speed. The problem now is I've lost/forgotten the nuanced Windows command-line steps (ping? tracert?) I used to troubleshoot or prove to myself or Comcast Xfinity what the culprit is. In the past it's sometimes been weird random radio interference but usually it's come down to modem T3 timeout issues caused by something before reaching my modem or anything directly connected to it, like with some pre-existing wall wire or connector or outside box. Right now of course Comcast Xfinity is saying they're seeing no problem and they just run me through the typical troubleshooting steps and things generally work at the time then get intermittent again randomly. When it's happening though typically the disconnects are frequent. Speed tests usually look OK, but sometimes up/down looks too low.

When I checked my modem logs in past weeks (it's been going on for maybe a month, I saw nothing significant. Now I see a full page of T3 timeouts about every few days... which matches the past experiences at my last place. I don't remember what to look at for power levels or error corrections etc... that's maybe a Comcast tech question. My modem is non-leased and maybe 5 years old but I haven't found anything to say it's failing.

Before fighting with a higher-level tech, I'd like to gather proof of where the problem is actually happening. While I vaguely remember to try ping and tracert, and I think I ran 4 command-line windows of them concurrently per Windows computer (wireless and wired) to track what was failing (connection to modem/router or internet), I don't remember exactly what I did, but I did gather enough last time to show the tech that the problem was not the modem/router. There were some failures with the WiFi pings/whatever, but it was miniscule compared to the internet failures (beyond my modem).

So far I've tried some things based on online search: ipconfig (to get my Default Gateway), pinging DNS servers - 1.1.1.1 (CloudFlare) and 8.8.8.8 (Google though I've read this isn't reliable anymore) - with and without the `-t` option (got random timeouts there), tracert on various websites (google.com, microsoft.com, yahoo.com, etc), and while I'm seeing timeouts and other odd behavior, I'm just not sure what I'm looking at yet nor how to prove to myself or a Comcast tech where the problem is.

Anyway, do you know what I'm talking about? Do you know the particular commands I should be running concurrently to gather up timeouts/errors/etc to show where the majority of the problem is happening? I thought I posted here but I'm not finding it now, so it must have been deleted or on an old account.

 

[helpstar]

just take a screenshot of your modem´s log with the T3 timeouts and send it to comcast. They should know that this is most likely a problem on their side. amplifier, copper cable, other external devices
https://www.speedguide.net/faq/docsis-t1-t2-t3-t4-timeout-errors-515

unplugging power and replugging the modem could help for a while though

 

[todafoa]

just take a screenshot of your modem´s log with the T3 timeouts and send it to comcast

I've done this in the past and gotten almost nothing but resistance and blame from Comcast, including a $30 charge from a new tech after he found an issue but then lazily put on the exit form that it was a "customer education issue" - and Comcast refused to refund it. That's partly why I'm here again. I thought the previous problems were just the age of my last home, but I'll try it again.

unplugging power and replugging the modem could help for a while though

I've done that so many times I stopped counting long ago. I do that when easier things don't work. Here sometimes it's worked sometimes it hasn't. Note that replacing the modem in the past has only worked 1 out of 10 times I've had issues with Comcast.

Anyway, I posted here for instructions on the ping/tracert thing... if somebody knows how that should be done, please reply.

 

[Ralston18]

@todafoa

Update your post to include full network and system specs:

Make and model: modem, router (or modem/router) if combined)?

Edit and correct (as necessary) the following network diagram to match your network environment:

ISP === (coax, DSL, fiber) ===> Modem ---->[WAN Port] Router [LAN Port] ----> [LAN Port] Office Wifi Access Point ~~~~> Wireless network devices

With other Router LAN ports -----> Wired network devices.

Post the edited network diagram as applicable.

Next, run "ipconfig /all" (without quotes) via the Command Prompt and post the results.

You should be able to copy and paste the results with no need to retype everything.

Objective being to determine if the issue is indeed a problem on your end or at Xfinitiy/Comcast's end.

May be something as simple as a failed/failing spliter or improperly terminated cable/connection.

More needs to be known before you can go forward.

And there are many online tutorials regarding "ipconfig /all", "ping", "pathping", and "tracert".

Key is to apply the tests methodically and target one end IP address. I suggest Google at 8.8.8.8 and 8.8.4.4

 

[todafoa]

Can you explain why you need information posted here for full network and system specs, modem router make and model, ISP, WAN and LAN Port, Wifi Access Point, and Wireless network devices? That seems like too much identifying info...

What I did before was run some commands on different Windows computers to check whether the connections were getting dropped more from the WiFi or the internet. The advice you're offering does not specifically seem to be doing the same thing. I'm looking for steps from someone that's done this before. If you have a particular online tutorial I should run, please paste the link. I've already gone through several and am not finding what I'm asking for.

Again: I need to discover if the problem is happening more at the WiFi level or the internet level. I did this before from steps someone here provided, I was hoping someone here now would have that. I'm just stabbing in the dark with trial-and-error at this point.

 

[Ralston18]

Those commands are for the most part diagnostic tools.

You can easily find tutorials and explanations regardng each of the tools.

Start here:

https://www.lifewire.com/what-is-a-private-ip-address-2625970

And you are free to redact something that personally identifies you.

Also, after reading back and noting "nuanced Windows command-line" , did you use netsh to troubleshoot?

References:

https://learn.microsoft.com/en-us/windows-server/networking/technologies/netsh/netsh-contexts

https://www.serverwatch.com/guides/netsh-commands/

Powershell can be used as well to obtain network information.

 

[drivinfast247]

I had this in the past and it was due to the node outside my home shifting when the ground froze in the winter. It was pulling cables apart.

 

[USAFRet]

I had this in the past and it was due to the node outside my home shifting when the ground froze in the winter. It was pulling cables apart.

I had similar, but the opposite.

Cox Cable, heat+humidity was causing an upstream box to fail intermittently.
It would fail 3-4-5 times a week.

It got to where I could predict the nightly fail to with 15-20 mins.

Call the Cox support line:
"Hi, I'd like to report my nightly internet outage."
'let me look....All looks OK sir'
"Give it a few minutes"
wait for it, wait for it....THERE!

"See? I don;t care if Mr. Cox hisself has to come out here and dig a ditch, FIX IT!"
Over time, everything from the interconnect box for the neighborhood, all the way to my PC and modem got replaced.
Still happened.

At one point, I had 3 service trucks and a supervisor car in the street in front of my house.

 

[todafoa]

Thanks for all the info.

I ended up following some connection error prompts in my phone, which led me to unplugging the WiFi for 10 seconds then plugging it back in (though I've done this many times already), and then after reconnect I got an error from the Xfinity app telling me my modem was not connected... following its prompts, it said the modem wasn't activated... following the prompts to activate it (which required Comcast rebooting it from their end), after activation everything started working flawlessly again.

I've had no issues since.

I think what happened is Comcast did some work somewhere during a regional power outage, which caused their system to miscommunicate with my modem, and then whatever the re-activation did corrected the desyncs or whatever the problem was. Note that my modem is not leased, I bought it years ago from Comcast's recommended compatibility list then, and Comcast doesn't update its firmware (and it's up to date as far as I can tell, and I don't see a way to update it anyway).

It'd be nice to have more clarity from Comcast or the phone or the modem, but if some random-looking adjustment fixes the issue, great.

 

[gggplaya]

What exact hardware do you have?

My motorola MB8611 had this issue and even though motorola had newer software to fix this, comcast did not validate and adopt the newer firmware version so it was always buggy with random dropouts.

I switched to the Arris S33 modem and my connection has been rock steady ever since.

 

[todafoa]

OK so after some months with no problem, a similar problem has manifested the last several months.

1. While on video meetings, I'll lose audio from them while they're speaking for several seconds. The period seems to be about every 1-1/2 minutes I'll lose 8 seconds from them. Nobody else hears interruptions. Any streaming video from them (cam or screenshare) doesn't show interruption while their audio is interrupted. Less frequently, and more intermittently, their video will freeze, but whether I lose their audio at the same time is basically random. I can't make any sense of this. It seems to happen most often with Zoom, almost never with Slack Huddle, but often with Google Meet. Streaming video like Netflix or YouTube or Paramount etc never interrupt, though sometimes I'll notice fuzzy picture.
2. While connected to ssh, I'll lose the connection every few minutes and have to re-login. I haven't timed this but it seems similar to the video meeting period.
3. OpenVPN will disconnect similarly to audio on Zoom/Meet and SSH connection. I've looked through logs and it just says keepalive timeout. The host says configuration is proper for timeout and it's a problem on my end. The VPN connection doesn't have an issue at another location.

I've tried the suggestions in this thread and a previous one (at another household) - https://forums.tomshardware.com/thr...g7550-modem-router-connection-issues.3774978/ - and so far tracert and ping looks fine, like this:

16488 packets transmitted, 16487 received, 0.00606502% packet loss, time 16516192ms

That's to my ISP's DNS. I've tried Google's and CloudFlare's, but there's no sign of trouble, unlike my previous thread. Of course, if the router has the problem, it'll reflect in a DNS ping. The problems happen on two different laptops years apart.

I'm flummoxed. When I'm at the office, using the same laptop, I have no internet issues. Comcast has told me they can come inspect the lines, but if they find any issue with my equipment, they'll charge me $100 complaining fee. Maybe it's worth it since most of the time that I have persistent internet trouble like this, Comcast found a problem on their end, though it was very difficult to get it inspected and found.

 

[Ralston18]

If all did indeed work for awhile (6 months) then my thought is that there is likely some degraded cable, connection, or device. Occurs over time and, depending on environment, sometimes faster, sometimes slower.

And the cause(s) of intermittent problems can be quite difficult to discover.

= = = =

Before calling Comcast there are a number of things you can do:

Start by physically inspecting as much of the network's cabling (coax?) and connections as you can.

From the incoming service cable to all endpoints.

Do so safely: no climbing on roofs etc..

Look for signs of damage: corrosion, rodent chews, kinked or bent wires, nails/staples, bare conductor showing. Loose or even flopping about cables.

Any splitters (filters)? They are made very cheaply and can (and do) go bad. Especially any splitters that are located outside and exposed to the elements.

Sometimes just disconnecting, cleaning/dusting, and reconnecting splitters can fix problems. If not - replace. Easy to do - I keep a couple of spares handy.

Likewise for barrel connectors, 90 degree turn adapters, and so forth.

Again, just disconnecting, blowing out dust, moisture, etc. and reconnecting can help.

What about uncapped or unterminated connections?

FYI:

https://blog.solidsignal.com/tutori... of,that forms a proper endpoint for a signal.

(I terminate unused connections. Especially exterior.)

Unforturnately, Comcast may come out, fix something, charge the $100, and leave. Then, sometime later the problem returns....

If anything, you may be able to call attention to something that seems amiss.

In all fairness, those techs are under a lot of pressure to get things fixed quickly. They will do what is most expedient and if the problem seems resolved - they leave.....