[arin-ppml] IPv6 policy: limitations on registrants?

[William Herrin]

On Fri, Jun 26, 2026 at 2:05 PM Eric C. Landgraf <echarlie at vt.edu> wrote:
> I'd like to see ULAs go the way of the dodo in enterprise environments.
> They have caused me nothing but problems, in part because of glibc's
> address selection algorithm.

Hi Eric,

Would you mind expanding on this? I have little operational experience
with IPv6 RFC 4193 addresses and I expect most folks here are in the
same boat. I understand that glibc would only be involved in setting
the order in which DNS lookup results are returned to a program. Is
that correct? When I look at my local /etc/gai.conf, it doesn't call
out fc00::/7 for different treatment than any other IPv6 address. For
off-Internet use, where does that end up creating a problem?

Regards,
Bill Herrin