dhcpcd-discuss

Hi

On 10/02/2020 08:35, nighthawk wrote:
> I am struggling with my configuration and I am not sure, if my
> ISP/router is acting wrong or if my config is screwed.
>
> I have a Linux system (Debian Buster with recent Kernel, 5.4 or 5.5,
> if that matters) and I am using dhcpcd 7.1.0 which comes precompiled
> with buster. I have eth0 with PVID 1 and additionally three VLANs
> added to it (20, 30 and 50). I want a normal IPv6 address on eth0 and
> one delegated prefix per VLAN, so I can give out IPv6 GUAs to systems
> on these networks. My configuration currently looks like this:
>
> option classless_static_routes
> slaac private
> noipv6rs
> noipv4ll
> leasetime 86400
>
> debug
>
> interface eth0
>          static ip_address=192.168.0.7/23
>          static routers=192.168.0.1
>          static domain_name_servers=192.168.0.1 2a02:xxx:2:a::1 2a02:xxx:2:b::1
>          inform 192.168.0.7/23
>          dhcp6
>          ipv6rs
>          iaid 9f:6e:c1:ee
>          ia_na
>          ia_pd 0 eth0.20/1/64 eth0.30/2/64 eth0.50/3/64
>          #ia_pd 30 eth0.30/0
>          #ia_pd 50 eth0.50/0
>          #ia_pd 20 eth0.20/0
>
> interface eth0.20
>          static ip_address=192.168.20.1/24
>          nodhcp
>          nodhcp6
>          iaid eb:59:07:c4
>
> interface eth0.30
>          static ip_address=192.168.30.1/24
>          nodhcp
>          nodhcp6
>          iaid 3d:20:bf:9e
>
> interface eth0.50
>          static ip_address=192.168.50.1/24
>          nodhcp
>          nodhcp6
>          iaid 0f:3e:35:e6
>
> This gives me exactly what I am looking for, but only for about 60
> seconds, which is the lifetime I am getting back in the PD reply.
> Everything works fine with just one VLAN and "ia_pd eb:59:07:c4
> eth0.20/0". This adds a /62 prefix to eth0.20, also with a lifetime of
> 60 seconds, but it's correctly being refreshed, so it stays around.
> I have also tried requesting multiple of these /62 networks instead of
> just one (commented out lines), but this does not work at all. If I
> try sla_ids 0, 1, 2 (instead of 1, 2, 3), only the first interface
> (sla_id = 0) gets a prefix assigned and also for just a minute or so.
> The rest is ignored.
>
> I have tried several other combinations of prefix masks, settings,
> different MAC for each VLAN interface and what feels like just about
> everything, but it still doesn't want to work. I have even set up
> another machine to see if maybe my router can only delegate one prefix
> at all, but the other machine is correctly getting one (a different
> one) as well. The above example is the closest I could get to what I
> want, now it just needs to work for more than a minute.
>
> Is my provider doing weird stuff or is my config still borked? Do
> newer dhcpcd versions maybe contain a fix for my scenario?

I know for sure newer dhcpcd has a lot of things fixed re PD. Also, i *think* 
the IAID is special cased in dhcpcd-7 which could be the issue you are seeing.
Try the latest dhcpcd-8 release.

Let me know!

Roy