On 14/3/23 13:15, David Wright wrote:
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)?
Yes. It was a result of the installation process identifying the
interface and generating the necessary /etc/network/interfaces
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
root@debian12:/etc/network# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default 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: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel
state UP group default qlen 1000
link/ether 08:00:27:18:b6:ac brd ff:ff:ff:ff:ff:ff
inet 10.31.40.166/24 brd 10.31.40.255 scope global dynamic enp0s3
valid_lft 76395sec preferred_lft 76395sec
inet6 2403:5800:c101:b700:a00:27ff:fe18:b6ac/64 scope global
dynamic mngtmpaddr
valid_lft 6277sec preferred_lft 2676sec
inet6 fe80::a00:27ff:fe18:b6ac/64 scope link
valid_lft forever preferred_lft forever
The difference to yours is I have a routable IPv6 address in addition
to the local link.
Your one has an autogenerated address
inet6 fe80::a601:23ff:fe45:6789/64
This is made as a function of your ethernet interface MAC address
I have an autogenerated address
inet6 fe80::a00:27ff:fe18:b6ac/64
and an address that must have been created as a result of an RA or DHCP
message as it is prefixed with my IPv6 address range
inet6 2403:5800:c101:b700:a00:27ff:fe18:b6ac/64
I note my two address have the same tails so I guess my routable IPv6
address is generated from the interface MAC address
I conclude there is no IPv6 DHCP involved but there must be something
that listens to RA announcements and generates a MAC derived address
from that.
I still need to know how to control that as there are options relating
to privacy that can do things like generate an expendable address in a
different way and later generate another and deprecate earlier addresses.
--
Jeremy
(Lists)
