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    WAN failover with only IPv4

    Scheduled Pinned Locked Moved General pfSense Questions
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    • D
      dkonigs
      last edited by

      If my question is better asked somewhere else, or if there's already a writeup giving a good answer, please redirect me. Its not the easiest thing to search for.

      My primary WAN connection provides both IPv4 and IPv6 connectivity, and all of that is configured and working correctly.

      My ISP has recently provided me with a cellular backup link that I'd like to work into my setup as a failover option for when my primary link goes down. There's just one catch... This backup link seems to only provide IPv4 connectivity.

      Is there any way to configure pfSense to do failover for my WAN connection, with an awareness that using the backup link requires shutting off IPv6 routing?

      I figure it would have to do the following to make this work:

      • Detect that the primary WAN connection is no longer functional
      • Switch to the backup WAN connection for IPv4
      • Send some sort of router advertisement informing clients that IPv6 no longer works, so they should stop trying to use it

      I hope this explanation makes sense. Doing the failover manually is quite tedious as I first have to switch the outgoing route, then disable router advertisements, then cycle the interfaces on all clients to get them to stop trying to send traffic via IPv6.

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      • stephenw10S
        stephenw10 Netgate Administrator
        last edited by

        Hmm, the difficult part there would be disabling the IPv6. That won't happen unless you have dynamic IPv6 and it loses it's address when the WAN goes down.
        Mmm, I'm not sure how that could be done in the current code. 🤔

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