Netgate Discussion Forum
    • Categories
    • Recent
    • Tags
    • Popular
    • Users
    • Search
    • Register
    • Login

    Routing question about unused ip6 subnets

    Scheduled Pinned Locked Moved IPv6
    4 Posts 3 Posters 729 Views
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • IsaacFLI Offline
      IsaacFL
      last edited by

      My ISP gives me a /56 of which so far I am using 3 /64 subnets and everything is working as it should.

      My question, do I need to do anything about the unused subnets. I notice if I ping or tracert an address in the unused range, that pfsense is sending it back out to the ISP, which promptly sends it back to pfsense, in a loop, until it TTL's out.

      Is there a set up in pfSense I should be doing to prevent that or is that considered ok?

      1 Reply Last reply Reply Quote 0
      • K Offline
        kpa
        last edited by

        Null route the /56 to the loopback interface on your pfSense with a static route at System->Routing->Static Routes. This will guarantee that any traffic going to the unallocated addresses will terminate at your pfSense without going anywhere. Traffic going to the /64s will of course take the correct route because the routes for the /64 are more specific than the route for the /56.

        1 Reply Last reply Reply Quote 0
        • johnpozJ Offline
          johnpoz LAYER 8 Global Moderator
          last edited by

          This would not happen from the public side.  While you can null route it sure - why should you need too.. Why would "YOU" be trying to accessing networks your not using?

          Anyone on the public side trying to access some unused prefix out of your /56 would just get sent to your pfsense wan via the route and pfsense would just drop it.

          An intelligent man is sometimes forced to be drunk to spend time with his fools
          If you get confused: Listen to the Music Play
          Please don't Chat/PM me for help, unless mod related
          SG-4860 25.07.1 | Lab VMs 2.8.1, 25.07.1

          1 Reply Last reply Reply Quote 0
          • IsaacFLI Offline
            IsaacFL
            last edited by

            I tried an online tool to traceroute to an address, and you are right about pfsense just dropping it, at least as far as I could tell.

            There shouldn't be any reason any internal device doing it, so it should be ok. I just wanted to make sure didn't get a nasty note from my ISP.

            1 Reply Last reply Reply Quote 0
            • First post
              Last post
            Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.