christoph ender's


saturday the 14th of october, 2023

no identification using MAC address with dhcpv6

I've been trying quite unsuccessful to exclude certain clients from getting an IPv6 via DHCP in a network. Since I just wanted to exclude specific interfaces I've used the MAC address instead of the DUID – the “DHCP unique identifier”, see DHCPv6. As it turns out, although the option to exclude/identify clients via MAC addresses may be present in dhcpv6 servers, it can't be used reliably at all. As the official kea documentation states: “Unfortunately, the DHCPv6 protocol does not provide any completely reliable way to retrieve that information.”