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    Power cycling upstream cable modem when the internet goes down

    Scheduled Pinned Locked Moved General pfSense Questions
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    • M
      marvosa
      last edited by

      I would start addressing the root issue vs treating the symptoms. If your modem is rented, then I would get on the phone with your ISP each and every time you have an issue so it's documented and make them fix it. You don't have to tolerate an unreliable modem. If it's happening on a regular basis, request a new modem and/or a tech to assess the root cause.

      After making multiple calls in my different houses, I've had bad modems, I've needed a signal booster, I also have a friend with similar symptoms as you... need a new line ran to his house... he was constantly power cycling both his modem and his router... and even bought a new router... until I urged him to call his ISP every time there was an issue. They finally sent out a tech to assess root cause and it turned out the company that installed his sprinkler system cut into the buried coax running to his house, which presented itself as an unreliable internet connection. After the new line was run, the instability issues went away completely.

      Basically, don't tolerate an unreliable internet connection. If you find yourself having to power cycle your modem more than once every ~8-12 months, there's an issue somewhere that needs to be addressed... and power cycling the modem isn't going to resolve it.

      JKnottJ 1 Reply Last reply Reply Quote 0
      • JKnottJ
        JKnott @pftdm007
        last edited by

        @pftdm007 said in Power cycling upstream cable modem when the internet goes down:

        GF wont let me do that...

        Ah,,, That's more like it. 😉

        How long is it between failures? If days, then perhaps a simple timer that kills the power in the middle of the night every day will do.

        PfSense running on Qotom mini PC
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        • JKnottJ
          JKnott @marvosa
          last edited by

          @marvosa said in Power cycling upstream cable modem when the internet goes down:

          and it turned out the company that installed his sprinkler system cut into the buried coax running to his house

          Quite so. I had a similar problem where my Internet connection and home phone, but not TV would fail. It took a lot of work on my part to prove the problem was not in my home (I have two feeds and it failed on both) and I wrote a shell script that pinged my ISPs router and recorded when it failed. The problem turned out to be a defective cable out near the street. The first guy who showed up insisted it was the cable running from my living room to my computer room (as described above) was bad and wanted to run a new cable along the baseboards, around door frames etc.. Since he couldn't explain why it wasn't the cable from the utility room, which was even older and installed by the previous cable company, that failed, I wouldn't let him do that.

          PfSense running on Qotom mini PC
          i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
          UniFi AC-Lite access point

          I haven't lost my mind. It's around here...somewhere...

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          • P
            pftdm007 @JKnott
            last edited by pftdm007

            @JKnott said in Power cycling upstream cable modem when the internet goes down:

            Ah,,, That's more like it.

            Yep

            @JKnott said in Power cycling upstream cable modem when the internet goes down:

            How long is it between failures?

            Well, like I said its not that often. Last time was maybe 2 weeks ago, ping times were in the 300-400ms which is abnormally high, and some stuff wasnt working right. A modem reboot helped.

            Before that, I think I had to reboot it back last summer. Never actually wrote down when I hard reset it, but I'm confident to say that it needs to be hard reset every 8-10 months or so. I dont think something is defective with my wiring, the modem or my ISP, I just think it is what it is.... Its a 40$ consumer grade modem.

            JKnottJ 1 Reply Last reply Reply Quote 0
            • JKnottJ
              JKnott @pftdm007
              last edited by

              @pftdm007

              Can you reach your modem when it fails. I know it's in bridge mode, but there may be an address that you can reach to configure the modem or check the status. On my Hitron modem, the address is 192.168.100.1.

              PfSense running on Qotom mini PC
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              UniFi AC-Lite access point

              I haven't lost my mind. It's around here...somewhere...

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              • stephenw10S
                stephenw10 Netgate Administrator
                last edited by stephenw10

                @pftdm007 said in Power cycling upstream cable modem when the internet goes down:

                Thomson DCM475

                Yup that. Your modem also looks to have a mgmt interface at that address if your ISP hasn't disabled it.
                You might need to add a virtual IP on WAN to access it though. Say an IPAlias as 192.168.100.10/24. Also assuming you are not using that subnet in your internal network anywhere.

                Try to ping it from Diag > Ping in pfSense.

                Steve

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                • stephenw10S
                  stephenw10 Netgate Administrator
                  last edited by

                  ...though it seems the interface may well only be available it the cable connection goes down.

                  Worth trying though. If it is available you can probably see the line stats etc.

                  Steve

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                  • chpalmerC
                    chpalmer
                    last edited by

                    That is a fairly old cable modem. If you are renting it then ask your ISP for a replacement and just let them know it is buggy. That model actually did have a firmware bug Im not sure ever got fixed.

                    http://192.168.1.1

                    The only reason you would not be able to see the gui is if the ISP has it shut off from your view. I do recommend a factory reset on it since it probably has not been done in years. It will pick up its config file when it restarts and come back online. But the reset may help get some of the bugs your experiencing out of it.

                    https://support.vmedia.ca/kb/a192/how-do-i-reset-the-thompson-technicolor-dcm475-476-.aspx

                    Triggering snowflakes one by one..
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                    • JKnottJ
                      JKnott @stephenw10
                      last edited by

                      @stephenw10 said in Power cycling upstream cable modem when the internet goes down:

                      You might need to add a virtual IP on WAN to access it though.

                      I don't have to with my Hitron.

                      PfSense running on Qotom mini PC
                      i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
                      UniFi AC-Lite access point

                      I haven't lost my mind. It's around here...somewhere...

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                      • stephenw10S
                        stephenw10 Netgate Administrator
                        last edited by

                        Yeah, it would depend on what the modem sees it's routing table, if it has a default route even.

                        Those devices are expected to be only modems so more likely to work as such. Routers running in 'modem mode' often end up with no default route so can only respond to traffic from their own subnet.

                        Steve

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                        • JKnottJ
                          JKnott @stephenw10
                          last edited by

                          @stephenw10

                          I would expect a modem in bridge mode wouldn't have much of a routing table. I suspect it uses deep packet inspection, to see which packets have that address for a destination.

                          PfSense running on Qotom mini PC
                          i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
                          UniFi AC-Lite access point

                          I haven't lost my mind. It's around here...somewhere...

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                          • Y
                            YannTKO
                            last edited by

                            You can setup a raspberry and use GPIO to pilot a relay.

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                            • johnpozJ
                              johnpoz LAYER 8 Global Moderator
                              last edited by johnpoz

                              If you were using unifi controller, ie you had some unifi AP for example - then this would do exactly what your asking for

                              https://store.ui.com/collections/unifi-accessories/products/unifi-smart-power
                              The UniFi SmartPower Plug is a device installed between the AC outlet and the power plug of an internet modem or router. The UniFi Network Controller continuously monitors availability of an internet connection. If the connection drops, the UniFi SmartPower Plug automatically restarts the modem or router by disconnecting power for a short period of time.

                              But yeah with all the smart plugs these days, I would think it would be pretty easy to rig something like this up..

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