4 ms·

> The non-interpretation-requirement makes DUIDs useless. If I must not compare it to a MAC address, I can't identify the IPv4 address assigned to the same host

> The non-interpretation-requirement makes DUIDs useless. If I must not compare it to a MAC address, I can't identify the IPv4 address assigned to the same host. You don't need to interpret a DUID. You can take a MAC address and generate a DUID-LL from it according to RFC 3315, then look for that in the DHCP traffic without ever interpreting DUIDs by simple equality comparison, while simultaneously scanning the DHCP (v4) traffic for the MAC you derived the DUID from. And if the thing you're looking for is not using DUID-LL, you're just as screwed as if your IPv4 product is randomizing its MAC address.

corty 6y ago
But that is not really "treating the DUID as opaque", is it? Also, there is still the problem of forcing devices into DUID-LL mode which is neither the default nor common. This requires manual configuration which is very bad for any large-scale use case.
- boomlinde 6y ago
  > But that is not really "treating the DUID as opaque", is it? Yes it is. Nowhere in this process do I need to take an existing DUID and treat it as anything other than an arbitrary sequence of bytes to be compared to another arbitrary sequence of bytes. > Also, there is still the problem of forcing devices into DUID-LL mode which is neither the default nor common. So maybe your use-case simply isn't common, perhaps because there are numerous ways to solve it that don't involve relying on ideal behavior in both DHCP v4 and v6 servers and clients. Take RFC 6939 for example, or just plain hostname based name assignments.
  - corty 6y ago
    And how do I get the initial hostname? Is it unique? Will it even be set? The hostname field is optional ;)
    - boomlinde 6y ago
      > Will it even be set? The hostname field is optional ;) Then of course, so is printing a barcode sticker representing the MAC address of the box you're installing. The basis for any solution that is going to let you install hundreds of hosts comfortably is the manufacturer going out of their way to support that, regardless of whether you're using plain DHCP or DHCPv6.

corty 6y ago

But that is not really "treating the DUID as opaque", is it? Also, there is still the problem of forcing devices into DUID-LL mode which is neither the default nor common. This requires manual configuration which is very bad for any large-scale use case.

boomlinde 6y ago
> But that is not really "treating the DUID as opaque", is it? Yes it is. Nowhere in this process do I need to take an existing DUID and treat it as anything other than an arbitrary sequence of bytes to be compared to another arbitrary sequence of bytes. > Also, there is still the problem of forcing devices into DUID-LL mode which is neither the default nor common. So maybe your use-case simply isn't common, perhaps because there are numerous ways to solve it that don't involve relying on ideal behavior in both DHCP v4 and v6 servers and clients. Take RFC 6939 for example, or just plain hostname based name assignments.
- corty 6y ago
  And how do I get the initial hostname? Is it unique? Will it even be set? The hostname field is optional ;)
  - boomlinde 6y ago
    > Will it even be set? The hostname field is optional ;) Then of course, so is printing a barcode sticker representing the MAC address of the box you're installing. The basis for any solution that is going to let you install hundreds of hosts comfortably is the manufacturer going out of their way to support that, regardless of whether you're using plain DHCP or DHCPv6.