Re: draft-cmetz-v6ops-v4mapped-api-harmful-00.txt and draft-itojun-v6ops-v4mapped-harmful-01.txt

[Juergen Schoenwaelder <j.schoenwaelder@iu-bremen.de>]

On Fri, Sep 12, 2003 at 11:33:56AM +0200, Mauro Tortonesi wrote:
> 
> instead, i think that i have far more arguments against usage of
> ipv4-mapped addresses on the api than on the wire (nowadays many unix oses
> have a very useful configuration option for dropping ipv6 packets with
> ipv4-mapped addresses).
> 
> first of all, they are a __nightmare__ for portability. and i think that
> this is such a valid argument by itself that we should deprecate
> ipv4-mapped addresses on the api immediately.
> 
> then my credo as a developer is "ipv6 is a brand new protocol", because
> AF_INET6 sockets have many options that are not applicable to ipv4
> connections, and writing applications that make use of the ipv4-mapped
> catch-all approach will be a great problem for developers (that will find
> themselves writing __a lot__ of checks/workarounds for special cases and
> will become crazy during the testing/debugging process).
> 
> moreover, i think that the ipv4-mapped catch-all approach in the
> development of ipv6-enabled apps may eventually become an obstacle for
> widespread adoption of production quality ipv6-enabled software (since it
> makes more difficult the use of the advanced ipv6 capabilities) and may
> lead the life of ipv4 to be longer than what all of us expect or desire.
> 
> so, i think that treating an ipv4 connection as an ipv6 connection to a
> ipv4-mapped endpoint is not only a bad development preactice but also
> semantically wrong.

Ack - I fully agree with your view of the situation.

/js

-- 
Juergen Schoenwaelder		    International University Bremen
<http://www.eecs.iu-bremen.de/>	    P.O. Box 750 561, 28725 Bremen, Germany