with dhcpv6 disabled in configuration we get an error about a referenced get_client_id string that seems to exist within the dhcp server " src/dhcp-4.4.2-P1/server/dhcpleasequery.c: switch (get_client_id(packet, &lq->client_id)) { src/dhcp-4.4.2-P1/server/dhcpv6.c:get_client_id(struct packet *packet, struct data_string *client_id) { src/dhcp-4.4.2-P1/server/dhcpv6.c: switch (get_client_id(packet, client_id)) { src/dhcp-4.4.2-P1/server/dhcpv6.c: switch (get_client_id(packet, client_id)) { src/dhcp-4.4.2-P1/server/dhcpv6.c: if (get_client_id(packet, &client_id) == ISC_R_SUCCESS) { src/dhcp-4.4.2-P1/server/dhcpv6.c: if (get_client_id(packet, &client_id) != ISC_R_SUCCESS) { src/dhcp-4.4.2-P1/server/ldap.c: if (get_client_id(packet, &client_id) != ISC_R_SUCCESS) " Same for 4.4.3 https://www.techwalla.com/articles/what-is-a-dhcp-client-id very interesting, that this exists for ipv6 and not ipv4, which means the client running dhclient provides with an "id" (most likely a Unique ID) to the server, if not MAC one is created. In any case this seems to need more work and research to be built with the entirety of ipv6 turned off at least on the dhcp side. Dhclient running with the -4 flag seems sufficient. openldap rebuilt