Re: [v6ops] draft-ietf-6man-rfc4291bis prohibiting non-/64 subnets

[Christopher Morrow <[e-mail]>]

On Fri, Feb 24, 2017 at 10:48 AM, Alexandre Petrescu <
[e-mail]> wrote:

>
>
> Le 24/02/2017 à 15:59, Christopher Morrow a écrit :
>
>>
>>
>> On Fri, Feb 24, 2017 at 9:09 AM, Alexandre Petrescu
>> <[e-mail] <mailto:[e-mail]>>
>>  wrote:
>>
>>
>> A question to Windows is the following: what prefixlen does it set
>> when the end user manually assigns an address on an interface without
>> specifiying a prefixlen?
>>
>>
>> I don't think this matters... 'end users' will in almost all cases
>> just attach and get connectivity.
>>
>
> Let me go next in cycle: what does linux do when one ifconfig add an
> IPv6 address without telling the plen?  Is it adding an entry in the rt
> table?  Which plen?  Is that plen normal?
>
>
still don't think this matters. If a user messes up what they type, they
messed up.
if the instructions aren't complete, they aren't complete and there will be
mistakes.
An interface configuration requires all proper parameters be set, or
problems will arise. Assumptions about current and future behavior are
proven wrong time and again.

non-deterministic behavior over time is the hallmark of this space...
please do not rely on defaults for hand-managed/bespoke configurations if
you expect things to work reliably and repeatably.

If they are in a place where someone says: "Hey, you should go
>> if/ipconfig ...." then .. they are 'consenting adults' and can do
>> whatever they please.
>>
>
> I assume you assume that ip/ifconfig by consenting adults means the
> adults type a plen in the CLI, right?
>
>
sure, or a script/program/etc does this, it's not important how the
'ifconfig' happens, it's important that when it happens the right
parameters are passed to the 'ifconfig' command.


> That makes it mandatory that the CLI _requires_ a plen, right?  That CLI
> should not allow silence for a plen parameter.
>
>
sure, or you are at the mercy of the implementor of that command:
  Today I like /64!
  It's tomorrow and now I like /62!!

don't rely on defaults.


> Because silent plen means 64.  And I dont think it's right to assume a
> by-default 64 plen.  Because many people think 64 is right and others
> think it's wrong, there does not seem to be a commonly agreed 'by
> default' value for plen.
>
>
correct, so.. be specific in your configuration effort please... which
again, means that the 'what is the default?" conversation is moot.


> Alex
>
>
>
>> again the proposed text (now 175+ messages back) really covers this
>> already..
>>
>