I want to assign multiple IPv6 to a server with multiple NIC.

As IPv6 RFC defines, each server has a unique DUID that can have one of the 3 formats (LL, LLT or enterprise). And each NIC has an IAID. So a request from NIC1 its the DUID and the IAID of the NIC1 and the request from NIC2 its the same DUID but the IAID its different.

The problem is that from a Centos box, when I ask for an IP in 2 different interfaces, I get the same IP.

I can't find how to specify host entry based on DUID and the IAID. I see some people generating a unique DUID based on the MAC of the NIC but this is not IPv6 RFC says.

What I tried is:

host entry1 {
    host-identifier option dhcp6.client-id 00:01:00:01:19:fc:f8:1c:52:54:00:7e:c9:ec;
    option dhcp6.ia-na "00:09:40:5d";
    fixed-address6 2001:db8:0:1::202;
 }
 host entry2 {
    host-identifier option dhcp6.client-id 00:01:00:01:19:fc:f8:1c:52:54:00:7e:c9:ec;
    option dhcp6.ia-na "00:7e:c9:ec";
    fixed-address6 2001:db8:0:1::201;
 }

This causes a Segmentation Fault in the client (what is scary...). I guess is not the right use for ia-na option but I don't see any other option.