Ipv6 - ULA and Prefix Delegation



  • I'm looking into implementing IPv6 however I'm running into an issue with how to handle addressing for internal resources such as DNS/AD/NAS/etc (additional servers). Typically with IPv4 this is not an issue because each device has it's own private address (ULA). However, with IPv6 you would have both a ULA and Global Address which need to be assigned to devices.

    The issue I'm running into is how I can go about utilizing DHCP to assign both a ULA and a Global Address to a single host. I know I could utilize slaac but my concern is there would be no way to truly know who connected to the network at the layer 3 level because I don't have a DHCP log to track devices. The only way I could see going about that is by watching for outbound network traffic from the said device that generates it's own SLAAC address. Additionally, not all devices support both protocols so if I leverage DHCPv6 for ULA and SLAAC for Global Address some devices might fail.

    How do most people hand this type of scenario?



  • @DiferMendos

    I don't know that you can do that. I just had a look at the DHCPv6 configuration and I don't see support for multiple prefixes. Also, you don't have to watch outbound traffic. Every device will periodically transmit a Neighbor Advertisement. These will be collected in a table on every device. In Linux, you'd use the ip -6 neighbor show command to see them. So, you can collect the info you want from that table.


  • LAYER 8 Global Moderator

    @DiferMendos said in Ipv6 - ULA and Prefix Delegation:

    ith IPv6 you would have both a ULA and Global Address which need to be assigned to devices.

    Why do you think your devices need both? You can work just fine with just a global.. You don't have to have ULA..


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