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    Ipv6 dhcp

    Scheduled Pinned Locked Moved IPv6
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    • JKnottJ
      JKnott
      last edited by

      @Derelict:

      Can I give a fixed ip range to different devices with SLAAC?

      No.

      Actually, you can.  Just assign a MAC address to whatever you want and the MAC based SLAAC will follow.

      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...

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      • JKnottJ
        JKnott
        last edited by

        @pox:

        @Derelict:

        Can I give a fixed ip range to different devices with SLAAC?

        No.

        Ok, back to dhcp then. I will try to increase the address range and see if I can hand out a /112 to each host

        Why a /112?  Normally, a network has a /64.  If all you want to do is experiment and don't need Internet access, you can use Unique Local Addresses. This provides a /48 that you can play with all you want.  If you do need Internet access, then you can use a tunnel, as suggested above, if your ISP doesn't provide IPv6.

        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...

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        • DerelictD
          Derelict LAYER 8 Netgate
          last edited by

          @JKnott:

          @Derelict:

          Can I give a fixed ip range to different devices with SLAAC?

          No.

          Actually, you can.  Just assign a MAC address to whatever you want and the MAC based SLAAC will follow.

          That is capital-U Ugly.

          Chattanooga, Tennessee, USA
          A comprehensive network diagram is worth 10,000 words and 15 conference calls.
          DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
          Do Not Chat For Help! NO_WAN_EGRESS(TM)

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          • JKnottJ
            JKnott
            last edited by

            @Derelict:

            @JKnott:

            @Derelict:

            Can I give a fixed ip range to different devices with SLAAC?

            No.

            Actually, you can.  Just assign a MAC address to whatever you want and the MAC based SLAAC will follow.

            That is capital-U Ugly.

            Perhaps, but I'm more interested in why DHCP is required.  I get the impression from the posts that the OP isn't quite sure about what he's doing.  With the /112 prefixes, he's doing something even more "ugly".  If he wants multiple networks, then he should get a decent size prefix from an ISP or tunnel, or use ULA to create his own /48.

            One thing I've noticed is a lot of people are stuck in the IPv4 mindset, where addresses are scarce.  They have a problem considering how that problem doesn't exist with IPv6.

            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
            • P
              pox
              last edited by

              @JKnott:

              @pox:

              @Derelict:

              Can I give a fixed ip range to different devices with SLAAC?

              No.

              Ok, back to dhcp then. I will try to increase the address range and see if I can hand out a /112 to each host

              Why a /112?  Normally, a network has a /64.

              That's for a host, not a network. I would like to give one host 65536 addresses via dhcp (or any other centrally managed way would be ok too).
              Or am I missing something obvious here?

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              • P
                pox
                last edited by

                @JKnott:

                @Derelict:

                @JKnott:

                @Derelict:

                Can I give a fixed ip range to different devices with SLAAC?

                No.

                Actually, you can.  Just assign a MAC address to whatever you want and the MAC based SLAAC will follow.

                That is capital-U Ugly.

                Perhaps, but I'm more interested in why DHCP is required.  I get the impression from the posts that the OP isn't quite sure about what he's doing.  With the /112 prefixes, he's doing something even more "ugly".  If he wants multiple networks, then he should get a decent size prefix from an ISP or tunnel, or use ULA to create his own /48.

                One thing I've noticed is a lot of people are stuck in the IPv4 mindset, where addresses are scarce.  They have a problem considering how that problem doesn't exist with IPv6.

                You are right that I am not sure of what I am doing :) I am playing with ipv6 and trying to understand how the pieces fit together.

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                • DerelictD
                  Derelict LAYER 8 Netgate
                  last edited by

                  What I tell people is to stop thinking about the 64 host bits entirely. To you they don't exist.

                  If you get a /48 you can assign 65536 /64 networks out of it. If you have a /56, 256 networks. A /60, 16. The 64 host bits simply do not exist.

                  Work in /64s. Save the subnetting longer than that for when you know you need it and can say why.

                  Chattanooga, Tennessee, USA
                  A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                  DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                  Do Not Chat For Help! NO_WAN_EGRESS(TM)

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                  • P
                    pox
                    last edited by

                    @Derelict:

                    If you want a host with 65536 addresses on it (good luck with that), just route a /64 to it.

                    While you might be able to coerce DHCP6 to do a /112 prefix delegation, why would you?

                    Or just pick a /112 range out of the /64 on the interface and assign them statically.

                    IPv6 doesn't do much to allow more hosts in one broadcast domain. 64K addresses is still not going to work very well if at all.

                    Maybe if you disclose what you are trying to do a better solution can be devised.

                    Sure: i have my internal lan with some servers. On one server, say hostname fritz, I have an ssh server, an http server that hosts 3 websites and an imap server.
                    I would like to publish all those services on the LAN with their own ip. So say
                    ssh server fdf5:4d23:aaaa:bbbb:0:0:0:1:22
                    website 1: fdf5:4d23:aaaa:bbbb:0:0:0:2:80 + 443
                    website 2: fdf5:4d23:aaaa:bbbb:0:0:0:3:80 + 443
                    website 3: fdf5:4d23:aaaa:bbbb:0:0:0:4:80 + 443
                    imap server: fdf5:4d23:aaaa:bbbb:0:0:0:5:993

                    How should I do that? Is there a best practice? Hardcoding the addresses on the host fritz does not seem right to me, because if someone else on the lan uses the same addresses I have a conflict.
                    I thought I could use the dhcpv6 to assign host fritz a /112, so host fritz knows he can use those addresses however he pleases, without having to worry of using someone else's addresses.
                    Is my reasoning wrong? Should I just hardcode the addresses on the server and be done with it?

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                    • DerelictD
                      Derelict LAYER 8 Netgate
                      last edited by

                      I would. Otherwise you have to worry about the addresses changing and updating DNS for all your hosts.

                      If you want to run servers you have to manage IP addresses. IPv6 doesn't change that.

                      Chattanooga, Tennessee, USA
                      A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                      DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                      Do Not Chat For Help! NO_WAN_EGRESS(TM)

                      1 Reply Last reply Reply Quote 0
                      • JKnottJ
                        JKnott
                        last edited by

                        That's for a host, not a network. I would like to give one host 65536 addresses via dhcp (or any other centrally managed way would be ok too).
                        Or am I missing something obvious here?

                        Yes.  While IPv6 supports multiple IPs on an interface (mine currently has 17) I suspect 65K is a bit much.  If you're running virtual machines for those servers, they will get there own individual addresses, if configured to bridge.

                        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...

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