Dynamic prefix assignment with static subnet host addresses



  • After a painless migration from an EdgeRouter to pfSense I ran into one minor issue with IPv6. My ISP pushes my prefix through DHCP-PD, and I can distribute that to my interfaces with 'track interface' and setting a prefix ID. The host address for the inside interfaces is now <prefix>:<prefix ID>:<IEU-64>/64. However, the EdgeRouter had the option of using static host addresses (as opposed to IEU-64)on such interfaces, essentially <prefix>:<prefix ID>::1/64.

    Is this feature available on pfSense? My ISP IPv6 assignment is static, so static interface assignment is the obvious workaround, but doing so dynamically does seem the more elegant solution.

    The relevant EdgeRouter config looks like this, it's the 'host-address ::1' part that I'm looking for.

    dhcpv6-pd {
        pd 0 {
          interface eth1 {
            host-address ::1
            prefix-id :1
            service slaac
          }
          interface eth2 {
            host-address ::1
            prefix-id :2
            service slaac
          }
        } 
    


  • I'm pretty sure that the only way this could be done in pfSense is with a virtual IP (Firewall > Virtual IPs) on the respective interface... but if your ISP ever delegates a different prefix to you, that virtual IP would need to be manually updated with the new prefix in order to function again.


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