[6bone] IPv6 application porting feedback solicited

[Stig Venaas]

On Fri, Jan 16, 2004 at 12:04:30PM +0200, Pekka Savola wrote:
[...]
> http://www.ietf.org/internet-drafts/draft-ietf-v6ops-application-transition-00.txt
> 
> If possible, please send feedback within a week.  Thanks.

I have a few items.

1. In 5.1 on presentation format, it talks about semi-colon where it
   should be colon. Quote:

     A particular problem with IP address parsers comes when the input
     is actually a combination of IP address and port.  With IPv4, these
     are often coupled with a semi-colon, like "192.0.2.1:80".  However,
     such an approach would be ambiguous with IPv6, as semi-colons are
     already used to structure the address.


2. I think it's too strong to say that it's bad practice to add AAAA
   record in DNS before all services support IPv6. There are many cases
   where one wants to start supporting IPv6 for some services, but are
   not able to IPv6 enable all. All client applications should be able
   to switch to v4 if v6 fails, and it shouldn't cause noticable delay
   for the user, unless there are some broken pieces in the network
   mishandling AAAA queries or responses. I agree it should be avoided,
   but to me "bad practice" sounds too strong.

3. Bind behaviour

   The document should perhaps say something about differences in bind
   behaviour. The main issue is whether you can first bind to v6 wild
   card address, and then the v4. It can be a pain to write applications
   that cope with this. In most cases, use of IPV6_V6ONLY should help,
   but unfortunately it doesn't say anywhere that it should affect bind
   behaviour. I think it's logical that it should though. The reason the
   v4 wild card bind fails on some systems, is that the v4 space is
   embedded into v6 space when using mapped addresses.

Stig