Re: Running code (Was: I-D Action: draft-ietf-6man-ipv6only-flag-03.txt)

[Brian E Carpenter <[e-mail]>]

On 2018-10-31 02:47, Philip Homburg wrote:
>> So, here's the challenge which you seem to be holding back from,
>> write down the actual rules. No hand waving that "that's a good
>> clue", but actual rules that "if you see <some observable state>
>> then <do some specific action>".

If by "rules" you mean "a typical heuristic", sure. But there will
be hosts that follow a different logic for their own good reasons.
That simply isn't the IETF's business.

The draft is quite clear on this:

   Dual stack hosts that have a good reason to use IPv4, for example for
   a specific IPv4 link-local service, can attempt to do so.  Therefore
   respect of the IPv6-Only flag is recommended, not mandatory, for
   hosts.

On 2018-10-31 04:18, Toerless Eckert wrote:
...
> IMHO:
> 
> If the host sees the ipv6only flag from all IPv6 routers, it MUST NOT
> perform IPv4 DHCP.

Who cares? Legacy hosts will try DHCP anyway. We don't want an updated
host to waste spectrum on this, but that's a SHOULD NOT, because such
traffic won't actually break anything.

    Brian