isc-dhcp-server: Using option dhcp-client-identifier in host declaration to identify a client

I had a similar issue with ISC DHCP 4.4.1, which I got working by prepending the id with a 0xff, i.e.:

host TestHost {
        option dhcp-client-identifier ff:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx;
        fixed-address 192.168.1.1;
}

The clue was in the tcpdump output of the request where it indicated the client id was hardware-type 255.

I've been facing this as well, and from what I've gathered the option is not officially supported in ISC DHCP 4.1 through 4.4. I've been playing with this as well as I have a trunk from my switch to my workstation such that I can monitor, and administer on any of my VLANs. Good news is that ISC is porting to a new DHCP software package called Kea, which is intended to have many more options available to you in both IPv4 and IPv6. Among these are DUID support, DDNS updates made on behalf of clients for both IP versions. No support is anticipated for Windows. Everything you've been asking about is in Kea, and as always; is available as a free download from ISC.