From: Nigel Gilbert <n.gilbert@...>
Date: 2003-06-20T05:38:47+09:00
Subject: Re: Summary: TCP/IP protocol and Net::HTTP

I spoke (wrote?) too soon!

The work around mentioned below does not seem to cure the problem (even 
building with --disable-ipv6 has no benefits).  Any other ideas?

Nigel


On Thursday, June 19, 2003, at 05:57 PM, Nigel Gilbert wrote:

> Thanks to all who have run trials and especially to Guy Decoux who 
> referenced an earlier discussion in ruby-talk that shed light on the 
> problem (which was: Net::HTTP.get_print 'ad.doubleclick.net', '/' 
> times out under MacOSX, but not on other platforms).  My summary is:
>
> On MacOSX, the implementation of getaddrinfo (which is used to 
> translate 'ad.doubleclick.net' into an IP address) starts by sending a 
> query to the doubleclick DNS server using an IPv6 format.  This DNS 
> server should either respond with the desired IP address, or decline 
> to do so.  In fact, the doubleclick DNS server makes no response at 
> all, and the Mac keeps waiting until eventually it times out.
>
> This explains why the problem only seems to occur only with the 
> combination of (a) doubleclick [their DNS server is unusual [1] in 
> that  it doesn't respond) and (b) MacOS X (this implementation of 
> getaddrinfo first tries an IPv6 format, and then backs down to an IPv4 
> format query, while other ruby implementations don't attempt an IPv6 
> query at all).
>
> The work around (not yet tried) is to rebuild ruby with the configure 
> options:
>
>           --enable-ipv6 \
>           --with-lookup-order-hack=INET
>
> which essentially says try IPv4 before IPv6
>
> The earlier ruby-talk thread related to all this starts at 66245
>
> I hope that the above options could become the default in the next 
> release.
>
> Nigel
>
> [1] Or perhaps one could say, 'buggy'
>
>
> On Thursday, June 19, 2003, at 05:33 PM, Michael Campbell wrote:
>
>> --- Jim Menard <jimm@io.com> wrote:
>>> Nigel Gilbert <n.gilbert@soc.surrey.ac.uk> writes:
>>>
>>>> If there is someone out there using MacOSX, could you try it and
>>> see
>>>> whether this theory is correct?  What you need to do is:
>>>
>>> I just tried under OS X and see the same timeout problem.
>>
>> As Guy mentioned, this is a doubleclick issue; they're not responding
>> to AAAA (ipv6?) requests, which is what Ruby is issuing.
>>
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>
>
>