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Issue with Comcast/xfinity

Scheduled Pinned Locked Moved General pfSense Questions
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  • C
    cptdevine
    last edited by Aug 22, 2020, 12:39 AM

    I have a weird one. Comcast did some construction and had my service down for a day. Once service was restored, I can no longer get my pfSense to maintain a connection. After about two minutes, the pfsense quits routing. Checking the gateway status, it shows offline. I can get it to work by doing a release/renew on the WAN DHCP lease, but it dies again after a couple of minutes.

    Internet works if plugged into other routers I tried a cisco ATA with a router as well as a TPlink router, both work. It also works connected directly to a laptop.

    Next I tried factory defaults on my pfsense. Same results. Tired with another PC running pfsense software. Same results.

    I tried a new in box sg1100. Same results.

    Comcast says everything is fine on their end and want to send a tech out.

    Cable modem is in bridge mode.

    All pfsense boxes were running the current version of software.

    Anyone got any ideas?

    Thanks,

    J 1 Reply Last reply Aug 22, 2020, 10:57 AM Reply Quote 0
    • J
      JKnott @cptdevine
      last edited by Aug 22, 2020, 10:57 AM

      @cptdevine

      I suspect it's a Comcast problem. Put an ordinary computer on the modem and see how long it stays up. If it fails too, there's nothing wrong with pfSense.

      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...

      1 Reply Last reply Reply Quote 0
      • C
        cptdevine
        last edited by Aug 22, 2020, 12:56 PM

        I've left a pc up for a few hours with a ping going, no problems. Right now I have a crappy TP link router that also has no problems.

        I tried updating my pfsense to one of the experimental builds and that went badly.

        Reinstalled 2.4.3 and ran through the wizard. Changed the LAN network to 10.0.10.0/24 and adjusted DHCP. Only thing weird I did was change the MAC on my wan interface.

        Still tanks after a couple of minutes.

        The only thing I can come up with is comcast's gateway does not respond to ICMP traffic, so the gateway monitoring thinks that gateway is down. I've tried disabling the monitoring and actions, but no luck.

        H 1 Reply Last reply Aug 22, 2020, 1:09 PM Reply Quote 0
        • H
          haxx @cptdevine
          last edited by haxx Aug 22, 2020, 1:10 PM Aug 22, 2020, 1:09 PM

          @cptdevine I just had a Comcast problem. I don’t know if it’s related to yours. I plugged in a laptop and Comcast seems to have locked in on the mac for the laptop. When I looked at the status of the Interfaces my WAN was not getting an IPV4 address. I unplugged the modem for about 2 minutes to clear out the settings and plugged the modem in again and let it completely fire up. Then I plugged in the firewall and Comcast correctly gave it an IP and everything worked.

          C 1 Reply Last reply Aug 22, 2020, 1:25 PM Reply Quote 0
          • C
            cptdevine @haxx
            last edited by Aug 22, 2020, 1:25 PM

            @haxx said in Issue with Comcast/xfinity:

            @cptdevine I just had a Comcast problem. I don’t know if it’s related to yours. I plugged in a laptop and Comcast seems to have locked in on the mac for the laptop. When I looked at the status of the Interfaces my WAN was not getting an IPV4 address. I unplugged the modem for about 2 minutes to clear out the settings and plugged the modem in again and let it completely fire up. Then I plugged in the firewall and Comcast correctly gave it an IP and everything worked.

            Yeah, Comcast does does a learn and lock on the first mac it sees when in bridge mode. You have to reboot to get it to bind to another device. This is why I changed the mac on mine to match the crappy TP link I have. This way I can move the cable modem between devices without having to wait for its slow reboot.

            Progress. Maybe.

            I defaulted the cable modem and with it doing NAT, my connection is stable.

            Of course this leaves me in a double NAT situation.

            Not sure what else to try so I'm going to swap cable modems. Maybe a surfboard will be better than that technicolor.

            1 Reply Last reply Reply Quote 0
            • C
              cptdevine
              last edited by Aug 22, 2020, 2:48 PM

              Update.

              I have swapped out the cable modem and this has solved my issue.

              Old modem was an Arris TG1682G. Upthread I said technicolor, I was wrong.

              New one is an Arris SB6190.

              I don't know if it was swapping the hardware or if the provisioning at comcast reset something, but it has been working for the last hour.

              1 Reply Last reply Reply Quote 0
              • C
                Carolina Quintero
                last edited by Apr 2, 2024, 7:42 PM

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