I’m running Linux Mint on a home server that happens to run pihole. Since it’s both a dhcp and dns server for my network, it has a static ip address. It has an ethernet connection as well as wifi and it’s always been my understanding that you can’t have two network interfaces sharing the same IP address, so I’ve been looking into ways to have one network adapter enabled and the other disabled and then if the network connection of the active device is lost, the other re-enables with the same IP address and disables the other device. This mostly work.

However while debugging one bit of software that seems to have a problem with me disabling my wifi adapter, I inadvertently enabled both the eth and wifi connections while each have the same, manually assigned ip address and everything so far just seems to work. I didn’t think this was possible and I’m wondering, should I expect problems? I can connect to the machine remotely fine, pihole and dvr services installed on the box work. Is there any reason to believe this won’t work?

  • non_burglar@lemmy.world
    2·
    24 hours ago

    Is it possible to configure interfaces this way? Yes.

    Will it work? No, not without bonding, and not with WiFi as one of the interfaces.

      • non_burglar@lemmy.world
        1·
        20 hours ago

        Oh, you are failing one over if the other fails? That’s not the same thing as configuring two interfaces with the same IP, gateway, at the same time, which is what I thought you were trying to do.

          • non_burglar@lemmy.world
            1·
            11 hours ago

            That’s because only one interface is really being used. A TCP session will reset if the hop count or metric changes all the time, the SYN/ACK wouldn’t work.

          • ReluctantMuskrat@lemmy.worldOP
            1·
            12 hours ago

            Thanks for sharing your experience… so it really does work! I mean it certainly seems to be working fine and I keep thinking I’m overlooking something. I feel like I’m in a love triangle with 2 girls fully aware of the other and they’re fine with it… this feels like a disaster but everyone seems to be happy!

            • atzanteol@sh.itjust.worksEnglish
              2·
              11 hours ago

              Yeah - I mean it’s technically “not ideal” but I simply don’t have any issues. I did have a windows computer that once complained about there being two devices on the network with the same IP but it didn’t stop it from working with it. I think that was some security software installed on that system though. This is the “less than ideal” part - it will look a bit suspicious if you have any security software that scans network traffic because “arp poisoning” is a common attack (basically stealing an IP address).

        • ReluctantMuskrat@lemmy.worldOP
          1·
          12 hours ago

          I simply wanted a fail-over but in the process got 2 interfaces with the same IP and I can’t find a problem with it 😄