Re: Debian 12 IPv6 client?

[David Wright <deblis@lionunicorn.co.uk>]

On Tue 14 Mar 2023 at 12:29:22 (+0800), jeremy ardley wrote:
> I am testing the alpha 2 release of Debian 12
> (I'm quite annoyed they have done away with /var/log/syslog)
> 
> My system is "pure" debian 12 and was net installed a few minutes
> before my checks. Nothing was changed from the original install.
> 
> My problem today is identifying what bit of the system is getting the
> IPv6 address. I can find nothing in journalctl

[ removed the typo ]

> cat /etc.network/interfaces
> # This file describes the network interfaces available on your system
> # and how to activate them. For more information, see interfaces(5).
> 
> source /etc/network/interfaces.d/*
> 
> # The loopback network interface
> auto lo
> iface lo inet loopback
> 
> # The primary network interface
> allow-hotplug enp0s3
> iface enp0s3 inet dhcp
> # This is an autoconfigured IPv6 interface
> iface enp0s3 inet6 auto
               ↑↑↑↑↑↑↑↑↑↑

I'm not very familiar with interfaces nowadays, but that looks
as if it's asking for enp0s3 to be autoconfigured with an IPv6
address. I thought that one got an IPv6 link address autoconfigured
anyway—I certainly do.

Did the debian-installer write that line (and comment)?

> Checking dhclient I see
> 
> ps ax | grep dhcl
>     354 ?        Ss     0:00 dhclient -4 -v -i -pf
> /run/dhclient.enp0s3.pid -lf /var/lib/dhcp/dhclient.enp0s3.leases -I
> -df /var/lib/dhcp/dhclient6.enp0s3.leases enp0s3
>     579 pts/0    S+     0:00 grep dhcl
> 
> So no dhclient -6 running.
> 
> root@debian12:/etc/network# journalctl | grep -i ipv6
> Mar 14 11:48:25 debian12 kernel: Segment Routing with IPv6
> Mar 14 11:48:25 debian12 kernel: In-situ OAM (IOAM) with IPv6
> Mar 14 11:48:25 debian12 kernel: mip6: Mobile IPv6
> Mar 14 11:48:26 debian12 kernel: IPv6: ADDRCONF(NETDEV_CHANGE):
> enp0s3: link becomes ready
> Mar 14 12:04:46 debian12 kernel: Segment Routing with IPv6
> Mar 14 12:04:46 debian12 kernel: In-situ OAM (IOAM) with IPv6
> Mar 14 12:04:46 debian12 kernel: mip6: Mobile IPv6
> Mar 14 12:04:48 debian12 kernel: IPv6: ADDRCONF(NETDEV_CHANGE):
> enp0s3: link becomes ready
> 
> 
> My question remains. What is getting the IPv6 address and how can I
> make configuration changes if required?

What's the output from:

  $ ip a

Mine (skipping lo):

  2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
      link/ether a4:01:23:45:67:89 brd ff:ff:ff:ff:ff:ff
      inet 192.168.1.14/24 brd 192.168.1.255 scope global dynamic enp3s0
         valid_lft 74247sec preferred_lft 74247sec
      inet6 fe80::a601:23ff:fe45:6789/64 scope link      ← this here
         valid_lft forever preferred_lft forever

Cheers,
David.