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Comcast gateways not responding to ping

Scheduled Pinned Locked Moved IPv6
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  • J Offline
    jhg
    last edited by Mar 27, 2024, 5:28 PM

    pfSense uses pings (icmp echo-request) to the gateway to determine gateway status.

    It appears that Comcast is configuring their gateways to not respond to echo-request, which makes them appear DOWN in the admin interface. The gateways are up and providing router-advertisement packets, just not responding to echo-request.

    For a while this problem only affected IPv4. I did a traceroute and discovered that the next hop host after the gateway would respond to ping, so I configured that as the monitor address. At that time the IPv6 gateway was responding to ping.

    Now they've disabled echo-reply on the IPv6 gateway.

    What is the "correct" way to deal with this? Is my traceroute solution appropriate, or should I be doing something else?

    pfSense CE on Beelink EQ12 (N100 CPU, dual 2.5Gbe Intel NICs)
    Hitron CODA56 - Comcast 2.5Gb cable

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    • S Offline
      skogs
      last edited by skogs Mar 28, 2024, 4:40 AM Mar 28, 2024, 4:29 AM

      For years instead of the comcast router for gateway up detection I use their v6 DNS server.
      2001:558:feed::2 or 2001:558:feed::1

      As I had to set IPv6 to DNS server for monitoring...I also use their IPv4 DNS servers for the same. System - Routing - Gateways - Edit ... 75.75.76.76 and the 2001:558:feed::2 have worked swimingly. I don't use those servers for actual DNS...but it proves that my local routers and equipment are up and that I can reach the core of their public services ok.

      (edited for clarity)

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