Re: Last Call: <draft-ietf-6man-rfc4291bis-07.txt> (IP Version 6 Addressing Architecture) to Internet Standard

[Alexandre Petrescu <[e-mail]>]

Le 22/02/2017 à 21:04, Brian E Carpenter a écrit :
> On 22/02/2017 22:41, Alexandre Petrescu wrote:
> <snip>
>
>>> Well that does two things: configures a 128 bit address (as Chris
>>> points out, *all* addresses are 128 bits, duh) and associates a
>>> prefix length with it, which afaik is optional.
>> The prefix length is not optional.  There is no system out there on
>> which one could configure a 128bit address without explicitely telling
>> '/128' or '/64' or '/something-else'.
> Wrong. Sorry to get all technical, but on Windows:
>
> C:\windows\system32>netsh interface ipv6 add address ?
>
> Usage: add address [interface=]<string> [address=]<IPv6 address>[/<integer>]
>               [[type=]unicast|anycast]
>               [[validlifetime=]<integer>|infinite]
>               [[preferredlifetime=]<integer>|infinite]
>               [[store=]active|persistent]
>               [[skipassource=]true|false]
>
> The [/<integer>] looks pretty optional to me. I just tried
>     netsh interface ipv6 add address 12 2001:db8:dead::beef
> and now I have three addresses:
>
> C:\windows\system32>netsh interface ipv6 show addresses
>
> Interface 12: Wireless Network Connection
>
> Addr Type  DAD State   Valid Life Pref. Life Address
> ---------  ----------- ---------- ---------- ------------------------
> Manual     Preferred     infinite   infinite 2001:db8:dead::beef
> Public     Preferred      1h54m9s      54m9s fd63:45eb:dc14:0:28cc:dc4c:9703:6781
> Other      Preferred     infinite   infinite fe80::28cc:dc4c:9703:6781%12
>
> When I try to ping 2001:db8:dead::cafe, I see what I expected in Wireshark:
> neighbour solicitations from 2001:db8:dead::beef to ff02::1:ff00:cafe.
> In other words, the new address is treated as on-link. I can't find any trace
> of an associated prefix entry.

Brian, I just discovered that one can see the associated prefix entry 
with "netsh interface ipv6 show route".

In this here setting I receive no RA.

When manually adding an address w/o specifying the plen on an interface 
it adds a /64 'connected' route and that's wrong.  The wrongness is in 
that '/64'.  Nobody told it '64' yet it assumed 64.  It's not wrong in 
adding a 'connected' route, but it's wrong in making that 64.

It's wrong because I may not want the entire 1::/64 to be 'connected', 
but maybe much less, especially when I manually configure.

Whereas in IPv6 it adds a /64, in IPv4 it adds a /8.  That '/8' comes 
from the fact that "1.1.1.1" is a class A; but in IPv6 there are no 
classes, right?  So why 64?

netsh
  interface ipv6 add address "Connexion au réseau local" address=1::1
  interface ipv6 show route



(warning: careful on a managed computer as it resists reboots and needs 
manual fixing afterwards).

Alex

> Maybe Linux is different.
>
>       Brian
>