Thanks for those links Bert.  I was able to confirm that my old ISP
does not, in fact, support IPv6 connections.  So that's why I thought
it was "working" when, in fact, it was just using IPv4.  So, there may
yet be an issue with Squeak and IPv6.


On Tue, Sep 24, 2013 at 10:08 AM, Bert Freudenberg <bert at freudenbergs.de> wrote:
>
> On 2013-09-24, at 11:03, Frank Shearar <frank.shearar at gmail.com> wrote:
>
>> It's actually harder to tell than that. If you say "connect to
>> www.kame.net" you'll issue some kind of DNS request. IPv6 addresses
>> are stored in AAAA records and IPv4 addresses in A records, so if you
>> ask for both you could end up connecting using either IPv6 or IPv4,
>> depending on how the socket code's written.
>>
>> For instance you could write the socket connection logic to say
>> 'resolve for AAAA and A, and iterate over the AAAA records trying to
>> connect to each IPv6 address in turn, falling back to the A records,
>> and bailing as a last resort'. I have no idea how Squeak's network
>> code will do this. Running strace would tell you the OS level calls
>> Squeak made, which should shed some light on the problem.
>>
>> Just yesterday I ran into a problem at work where 'localhost' meant
>> 127.0.0.1 on my machine, and ::1 on a build slave. That wasn't fun to
>> understand.
>>
>> frank
>
>
> The old socket plugin code uses gethostbyname() and returns the first of the list of answers, without even checking that the answer is, in fact, an IPv4 address.
>
> The new socket plugin code uses getaddrinfo() and answers the full list of addresses, so the image can figure out which one it prefers.
>
> Both old and new is still supported in the plugin so it's up to the image to use either.
>
> NetNameResolver addressesForName: 'www.google.com'
> ==> an OrderedCollection(
>         173.194.44.51(muc03s08-in-f19.1e100.net),0(0)-inet4-stream-tcp
>         173.194.44.48(muc03s08-in-f16.1e100.net),0(0)-inet4-stream-tcp
>         173.194.44.49(muc03s08-in-f17.1e100.net),0(0)-inet4-stream-tcp
>         173.194.44.52(muc03s08-in-f20.1e100.net),0(0)-inet4-stream-tcp
>         173.194.44.50(muc03s08-in-f18.1e100.net),0(0)-inet4-stream-tcp
>         2a00:1450:4016:803::1011(muc03s08-in-x11.1e100.net),0(0)-inet6-stream-tcp)
>
> If you use "NetNameResolver addressForName: ..." then it will either use the old code (if forced by preference) or answer the first of the addresses.
>
> I myself cannot easily test IPv6 as it's not natively supported by my ISP, yet.
>
> If it did, then both of these should work equally:
>
>         HTTPSocket httpGetDocument: 'ipv4.whatismyv6.com'
>         HTTPSocket httpGetDocument: 'ipv6.whatismyv6.com'
>
>
> - Bert -
>
>
>