Re: Last Call: <draft-ietf-6man-rfc4291bis-07.txt> (IP Version 6 Address

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