Encontrei uma resposta aqui link
Essencialmente, o dhcpd tem uma maneira de adicionar ganchos para eventos, portanto, em um registro IPv4, chame um script que gere o endereço IPv6 padrão baseado em MAC e registre isso.
ATUALIZAÇÃO: (Estou usando o ICH DHCP 4.1)
Ao usar o gancho "on commit", ele remove a atualização dinâmica existente e você precisa copiá-la para a seção "on commit", a minha agora é assim:
on commit {
if (not static) {
# Setup IPv6 Address
set new-ddns-fwd-name = pick-first-value(ddns-hostname, host-decl-name);
if (exists host-name and option host-name ~~ "^[a-z0-9.-]+$") {
set new-ddns-fwd-name = option host-name;
} elsif (exists dhcp-client-identifier and option dhcp-client-identifier ~~ "^[a-z0-9.-]+$") {
set new-ddns-fwd-name = substring(option dhcp-client-identifier, 1, 50);
} elsif (new-ddns-fwd-name = "") {
set new-ddns-fwd-name = binary-to-ascii (16, 8, "-",
substring (hardware, 1, 6));
}
set ddns-fwd-name = new-ddns-fwd-name;
execute ("/opt/bin/ddns-ipv6", ddns-fwd-name, ucase(
binary-to-ascii(16, 8, ":", substring(hardware, 1, 6))),
binary-to-ascii(10, 8, ".", leased-address));
unset new-ddns-fwd-name;
switch (ns-update (not exists (IN, A, ddns-fwd-name, null),
add (IN, A, ddns-fwd-name, leased-address,
lease-time / 2))) {
default:
unset ddns-fwd-name;
break;
case NOERROR:
set ddns-rev-name =
concat (binary-to-ascii (10, 8, ".", reverse (1, leased-address)), ".",
pick (config-option server.ddns-rev-domainname,
"in-addr.arpa."));
switch (ns-update (delete (IN, PTR, ddns-rev-name, null),
add (IN, PTR, ddns-rev-name, ddns-fwd-name, lease-time / 2)))
{
default:
unset ddns-rev-name;
on release or expiry {
execute ("/opt/bin/ddns-ipv6", "-d", pick-first-value(ddns-hostname, host-decl-name));
switch (ns-update (delete (IN, A, ddns-fwd-name,
leased-address))) {
case NOERROR:
unset ddns-fwd-name;
break;
}
on release or expiry;
}
break;
case NOERROR:
on release or expiry {
execute ("/opt/bin/ddns-ipv6", "-d", pick-first-value(ddns-hostname, host-decl-name));
switch (ns-update (delete (IN, PTR, ddns-rev-name, null))) {
case NOERROR:
unset ddns-rev-name;
break;
}
switch (ns-update (delete (IN, A, ddns-fwd-name,
leased-address))) {
case NOERROR:
unset ddns-fwd-name;
break;
}
on release or expiry;
}
}
break;
}
}
}