Hello 3,

As Simon has previously pointed out a number of times, a client must send 
multiple IA_NA’s in a request to get multiple addresses. This is discussed in 
section 6.6 Multiple Addresses and Prefixes of RFC8415 
(https://datatracker.ietf.org/doc/rfc8415/ 
<https://datatracker.ietf.org/doc/rfc8415/>)

As per the Kea documentation, you can find the specific reference to how we 
handle Multiple Addresses with Host Reservations in this section in the ARM: 
https://kea.readthedocs.io/en/kea-2.2.0/arm/dhcp6-srv.html#host-reservations-in-dhcpv6
 
<https://kea.readthedocs.io/en/kea-2.2.0/arm/dhcp6-srv.html#host-reservations-in-dhcpv6>

> DHCPv6 allows a single client to lease multiple addresses and multiple 
> prefixes at the same time. Therefore ip-addresses and prefixes are plural and 
> are actually arrays. When the client sends multiple IA options (IA_NA or 
> IA_PD), each reserved address or prefix is assigned to an individual IA of 
> the appropriate type. If the number of IAs of a specific type is lower than 
> the number of reservations of that type, the number of reserved addresses or 
> prefixes assigned to the client is equal to the number of IA_NAs or IA_PDs 
> sent by the client; that is, some reserved addresses or prefixes are not 
> assigned. However, they still remain reserved for this client and the server 
> will not assign them to any other client. If the number of IAs of a specific 
> type sent by the client is greater than the number of reserved addresses or 
> prefixes, the server will try to assign all reserved addresses or prefixes to 
> the individual IAs and dynamically allocate addresses or prefixes to the 
> remaining IAs. If the server cannot assign a reserved address or prefix 
> because it is in use, the server will select the next reserved address or 
> prefix and try to assign it to the client. If the server subsequently finds 
> that there are no more reservations that can be assigned to the client at 
> that moment, the server will try to assign leases dynamically.

Thanks,
Dan Theisen
ISC Escalations Engineer

> On Nov 17, 2022, at 10:21 AM, 3 <[email protected]> wrote:
> 
>>> seriously? i just killed rad and reconnected the client. shall i tell you 
>>> what has changed? NOTHING! do you think the dhcp client in windows is 
>>> wrong? if so, then will have to redo the rfc for windows, and not windows 
>>> for rfc. lol
>> Did you tell the client to release its leased address ? No ? In that case, 
>> the DHCP client will continue to keep the address configured until it 
>> expires (or another network event causes it to become invalid).
> dear, do you take me for an idiot? of course i deleted the leased address and 
> looked at the dhcpv6 frames. i tell you again- check your statements in 
> practice, otherwise it will turn into trouble for you someday.
> 
>>> exactly, there may not be a router. do you know what the problem with 
>>> link-local addresses is? they can be random!
>> They shouldn’t be random, on an ethernet network they will be based on the 
>> MAC address and will be stable as long as the MAC address is stable.
> so, i see that you know even less than me. this is due to a device tracking 
> issue. it's a long time to write, google it.
> ps: damn it, i came here for help, and it turns out i have to help %)
> 
>>> and often this is not what we need. besides, if everything is so good with 
>>> link-local, then why do local unicast addresses exist? ;)
>> Different address types have different uses.
>> You may have seen 169.254.n.n addresses in the IPv4 world when there is no 
>> DHCP server present. These self-assigned addresses fulfil a similar role to 
>> some of the uses for IPv6 link local addresses - specifically they allow a 
>> group of devices to use multicast DNS to find each other. mDNS underpins a 
>> number of discovery functions around finding printers, network shares, etc.
>> But in a managed network, you would normally prefer to manage the addresses 
>> you put into the internal DNS. So rather than use a link local address for 
>> your internal web server, you would setup a ULA prefix and use that 
>> internally. As it’s independent of any upstream connections, it’s stable and 
>> under your control.
>> For networks without a full time management team (even if that is a one 
>> person team), setting that up is usually “too hard” and not required. For a 
>> typical home network, the users don’t care about all that, they just want 
>> stuff “to work”.
> i'm not stupid enough to tell me the basics ;)
> 
>> If you have a prefix delegation, it’s (in most cases) not very useful unless 
>> the rest of the network knows how to reach that prefix. But even where there 
>> isn’t any routing involved, you still need RAs to tell devices what 
>> prefix(es) are available.
> CHECK YOUR STATEMENT IN PRACTICE! >:(
> 
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