Hi, Brian,
On 31/3/20 00:29, Brian E Carpenter wrote:
It seems that the router must be setting both the A bit (use SLAAC) and the M bit (use DHCPv6).
FWIW, my Sagemcom router provided by my ISP does the same (set both A
in PIOs, and M (and O :-) ) in the RA). UBuntu reacts as descirbed by
the OP.
So the host is obeying both. There's no real harm in it, in most circumstances.
Not sure I would clasify it as "harm", but:
my ubuntu box does rfc7217+rfc4941. But since the M bit is set, it
configures a DHCPv6-leased address... with a predictable IID. (
apparently the CPE has a poool that starts at ::1000, and leases
addresses incrementally).
Certainly, that's not nice.
Besides, if folks are concerned about the number of addresses in use (as
some did in recent 6man discussions), one would say this is a
low-hanging fruit: an address that is configured, and will *never* be used.
Fixing the ambiguity about what hosts should do about this has often been
discussed in the IETF but there's never really been evidence that it's worth
doing.
FWIW, me, even if it was just for the sake "clarity", that would be
worth doing.
Thanks!
Cheers,
--
Fernando Gont
e-mail: [email protected] || [email protected]
PGP Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076 FFF1
