Re: sockets APIs extensions for Host Identity Protocol

[Stephane Bortzmeyer <[e-mail]>]

On Tue, May 08, 2007 at 11:19:51PM -0400,
 Keith Moore <[e-mail]> wrote 
 a message of 29 lines which said:

> In those cases, the programmers are also crippled and prevented from
> dealing effectively with various cases that are now increasingly
> common in the Intenet today: NATs, multiple addresses for source and
> destination (not all of which work equally well), IPv4 vs IPv6 (for
> which the default address selection rules are woefully inadequate),
> multi-faced DNS, LLMNR, etc.

I strongly object to the idea of application programmers dealing with
NAT, IPv4 vs. IPv6 or source address selection for the eternity. The
wiring of level-3 details in the applications is precisely what makes
the transition to IPv6 so difficult. Applications should not have to
be "ported to IPv6". They should work the same with both level-3
protocols (and, indeed, they do, in every language but C).

If the IPv6 problems are to be useful, it is in showing that there is
ZERO probability of splitting the identifier and the locator if we
have to change the applications.

I also really doubt that the typical application programmer is able to
do a better job than the kernel / libraries to, choose the source
address or other level-3 features. Plus, IMHO, if someone must
influence this selection, it should be the system and network
administrator, not the application programmer.

> only if you want to limit the deployability and/or efficiency of
> your application.

As an user, I would be very afraid of an application which tries to
play tricks with NAT...