On Tue 14 Mar 2023 at 15:00:20 (+0800), Jeremy Ardley wrote: > 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.
I get my link address without any configuration by me: nothing like iface enp0s3 inet6 auto is involved. So that line, unfamiliar to me as a bullseye user, may be the cause of your routable address problem. What happens if you take it out? Cheers, David.
