dhcpcd-discuss

Hi Sébastien

On 23/09/2018 18:25, Sébastien Luttringer wrote:
> I use dhcpcd to manage an IPv6 network on an Arch Linux server.
> I request an IPv6 prefix and assign a static IP inside.
> dhcpcd get the prefix delegation route and configure the static ipv6, but it
> exits after 30s.
> Is this behavior expected? Why dhcpcd wait for a IP as we have a static ip
> defined and we got a PD? Is there a way to disable the ip wait mechanism?
>
> Configuration in /etc/dhcpcd.conf is the following:
> interface eth0
> ipv6only
> ipv6rs
> duid
> vendorclassid
> static ip6_address=2002:bc9:3173:200::42
> ia_pd 0 eth0/0
>
> # /usr/bin/dhcpcd -d eth0
> dhcpcd-7.0.8 starting
> eth0: executing `/usr/lib/dhcpcd/dhcpcd-run-hooks' PREINIT
> eth0: executing `/usr/lib/dhcpcd/dhcpcd-run-hooks' CARRIER
> DUID 00:03:00:01:25:xx:xx:xx:xx:xx
> eth0: IAID cb:0b:82:2b
> eth0: IA type 25 IAID 00:00:00:00
> eth0: adding address 2002:bc9:3173:200::42/128
> eth0: pltime infinity, vltime infinity
> eth0: executing `/usr/lib/dhcpcd/dhcpcd-run-hooks' STATIC6
> eth0: delaying IPv6 router solicitation for 0.3 seconds
> eth0: reading lease `/var/lib/dhcpcd/eth0.lease6'
> eth0: rebinding prior DHCPv6 lease
> eth0: delaying REBIND6 (xid 0x8167ee), next in 0.0 seconds
> eth0: broadcasting REBIND6 (xid 0x8167ee), next in 1.0 seconds
> eth0: REPLY6 received from 2002:bc9:2::2:272:2
> eth0: 2002:bc9:3173:200::/56 will expire before renewal
> eth0: ignoring T1 43200 to due address expiry
> eth0: renew in 13500, rebind in 21600, expire in 43200 seconds
> lo: adding reject route to 2002:bc9:3173:200::/56
> eth0: writing lease `/var/lib/dhcpcd/eth0.lease6'
> eth0: delegated prefix 2002:bc9:3173:200::/56
> eth0: DHCPv6 server does not support OPTION_PD_EXCLUDE
> eth0: executing `/usr/lib/dhcpcd/dhcpcd-run-hooks' REBIND6
> waiting for an IP address
> eth0: soliciting an IPv6 router
> eth0: sending Router Solicitation
> eth0: Router Advertisement from fe80::235:1aff:fe3f:1b67
> eth0: adding default route via fe80::235:1aff:fe3f:1b67
> eth0: executing `/usr/lib/dhcpcd/dhcpcd-run-hooks' ROUTERADVERT
> eth0: No DHCPv6 instruction in RA
> timed out
> dhcpcd exited


Wow.
This is an edge case I'm not entirely sure I want to work around.

Firstly, you are delegating to the same interface you're requesting on 
and dhcpcd correctly warns that your DHCPv6 server does not support this 
(OPTION_PD_EXCLUDE is missing from it's reply).
If it did, then dhcpcd would assign an IPv6 address to the interface and 
it would fork to the background correctly.

Secondly, if you ran dhcpcd in master mode (ie not specify an interface 
on the command line or pass the -M flag) it would also fork to the 
background correctly.

Roy