On Thu, Nov 16, 2023 at 07:10:32AM -0600, Michael S. Keller via Dng wrote:
> /etc/network/interfaces:
>
> auto eth0
> iface eth0 inet6 dhcp

I see from output you posted previously your router supports stateful
address configuration, but you didn't post any output regarding
autonomous address configuration. I don't expect the following to make
a difference, but just in case, can you change in
/etc/network/interfaces:

iface eth0 inet6 dhcp

to:

iface eth0 inet6 auto

followed by a reboot for good measure to see if that makes a difference?

> For the desktop-to-server direction, Wireshark shows TCP Dup ACKs, Spurious
> Retransmissions, TCP Resets. I can send the output, if it helps.

Based on your description, I don't think sending the actual output
would be enlightening. However, if you would like to share the output
from tcpdump, or some textual equivalent from wireshark, I can take a
look. If you share an image and not something in text form, I won't be
able to help. Also, if this is lengthy, it's probably a good idea to
just post a link to it rather than sending all of it to the entire
list membership.

>
> If I run ndisc6 from the server, against the desktop's IPv6 address, only
> one MAC is returned, so I hopefully there's not a duplicate address.

That's as it should be.

Greg


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