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References: <B3F902EF-8956-4E30-A1BA-7D7B254459E3@malikania.fr>
In-Reply-To: <B3F902EF-8956-4E30-A1BA-7D7B254459E3@malikania.fr>
From: Konstantin Kulikov <k.kulikov2@gmail.com>
Date: Thu, 29 Apr 2021 10:02:05 +0300
Message-ID: <CAD+eXGRFsatDvm7jm7tRP35BLGsfZk3Q9pTuDkrFNyskZGV+tA@mail.gmail.com>
Subject: Re: dhcpcd not updating /etc/resolv.conf
To: David Demelier <markand@malikania.fr>
Cc: ~alpine/users@lists.alpinelinux.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

You can add a bunch of printfs in /usr/lib/dhcpcd/dhcpcd-hooks/20-resolv.co=
nf

On Thu, Apr 29, 2021 at 9:05 AM David Demelier <markand@malikania.fr> wrote=
:
>
> Hey there,
>
> For some reasons I could not get dhcpcd to update /etc/resolv.conf on Alp=
ine 3.13 (aarch64) on a Raspberry Pi.
>
> The system:
>
> Linux vanille 5.10.29-0-rpi4 #1-Alpine SMP PREEMPT Mon Apr 12 15:55:08 UT=
C 2021 aarch64 Linux
>
>
> The daemon acquire a lease correctly in both eth0 and wlan0 and set defau=
lt route, IP address and such (I can ping every IP address) but for some re=
asons the resolv.conf file is empty.
>
> Example of syslog messages when it receives DHCP lease:
>
> Apr 28 22:42:11 vanille daemon.info [3203]: wlan0: connected to Access Po=
int `Bbox-4D2019EB'
> Apr 28 22:42:11 vanille daemon.info [3203]: eth0: waiting for carrier
> Apr 28 22:42:11 vanille daemon.info [3203]: DUID 00:01:00:01:27:87:66:06:=
dc:a6:32:5f:6f:dc
> Apr 28 22:42:11 vanille daemon.info [3203]: wlan0: IAID 32:5f:6f:dc
> Apr 28 22:42:11 vanille daemon.info [3203]: wlan0: adding address fe80::d=
ea6:32ff:fe5f:6fdc
> Apr 28 22:42:11 vanille daemon.info [3203]: wlan0: soliciting an IPv6 rou=
ter
> Apr 28 22:42:12 vanille daemon.info [3203]: wlan0: rebinding lease of 192=
.168.1.97
> Apr 28 22:42:12 vanille daemon.info [3203]: wlan0: probing address 192.16=
8.1.97/24
> Apr 28 22:42:17 vanille daemon.info [3203]: wlan0: leased 192.168.1.97 fo=
r 86400 seconds
> Apr 28 22:42:17 vanille daemon.info [3203]: wlan0: adding route to 192.16=
8.1.0/24
> Apr 28 22:42:17 vanille daemon.info [3203]: wlan0: adding default route v=
ia 192.168.1.254
> Apr 28 22:42:17 vanille daemon.info [3203]: forked to background, child p=
id 3221
> Apr 28 22:42:25 vanille daemon.warn [3221]: wlan0: no IPv6 Routers availa=
ble
>
> And the ip a show:
>
> 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen =
1000
>     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
>     inet 127.0.0.1/8 scope host lo
>        valid_lft forever preferred_lft forever
>     inet6 ::1/128 scope host
>        valid_lft forever preferred_lft forever
> 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qle=
n 1000
>     link/ether dc:a6:32:5f:6f:da brd ff:ff:ff:ff:ff:ff
>     inet 192.168.1.95/24 brd 192.168.1.255 scope global dynamic eth0
>        valid_lft 86054sec preferred_lft 75254sec
>     inet6 fe80::dea6:32ff:fe5f:6fda/64 scope link
>        valid_lft forever preferred_lft forever
> 3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast sta=
te UP qlen 1000
>     link/ether dc:a6:32:5f:6f:dc brd ff:ff:ff:ff:ff:ff
>     inet 192.168.1.97/24 brd 192.168.1.255 scope global dynamic wlan0
>        valid_lft 86071sec preferred_lft 75271sec
>     inet6 fe80::dea6:32ff:fe5f:6fdc/64 scope link
>        valid_lft forever preferred_lft forever
>
> And the resolv.conf once done:
>
> # Generated by dhcpcd
> # /etc/resolv.conf.head can replace this line
> # /etc/resolv.conf.tail can replace this line
>
> The /etc/dhcpcd.conf is quite simple:
>
> hostname
>
> interface eth0
>         metric 10
>
> interface wlan0
>         metric 20
>
> If I install openresolv, dhcpcd calls it but the generated file is also e=
mpty (only the header changes). However using busybox=E2=80=99s udhcpd work=
s fine and generates the appropriate nameserver line in /etc/resolv.conf.
>
> I=E2=80=99ve been using dhcpcd for years without any problems on many mac=
hines but now I=E2=80=99m completely out of ideas about this problem. I als=
o prefer dhcpcd over busybox=E2=80=99s udhcpd/ifplugng because it does a ve=
ry good job about hotplugging interfaces and non blocking boot (also offers=
 a GTK UI).
>
> Any idea would be appreciated.