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Perl and IPv6?

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Calle Dybedahl
December 18, 2008 03:11
Perl and IPv6?
Message ID:
Hello. I'm currently consulting for the Swedish ccTLD registry,
helping them write a DNS zone-checking tool. In Perl, obviously. You
can find it at if you're
interested. Part of the registry's task is to "promote the positive
development of the Internet in Sweden". As part of that, they're
pushing the use of DNSSEC and IPv6. Which means that the tool needs to
deal with those. DNSSEC is no problem. Unfortunately, it's starting to
look like IPv6 is.

There is basic IPv6 functionality. That's not a problem. Some modules
can use it, including fortunately Net::DNS, or this tool probably
wouldn't have been written in Perl to begin with.

Where I first ran into trouble was the test that checks if the mail
address in SOA records is deliverable. One of the people involved
reported this test giving spurious failures for IPv6-only mail
servers. Which turns out to be because Net::SMTP is not v6-aware.
"Ok," I thought. "How hard can that be to fix?"

I'm still trying to figure that out.

At first, it looked like it would simply be a matter of having it use
IO::Socket::INET6 instead of IO::Socket::INET, and I even sent off a
patch to Graham Barr to do that for most of the libnet modules (if the
INET6 is available, of course). Unfortunately I later saw that the
README for the INET6 module specifically recommends not doing that,
due to problems with "some given corner cases", and that the ability
of the INET6 module to handle IPv4 may be removed in the future. Which
punts a whole lot of work up to the code wanting to connect over the
Internet. Which at least at a first look seems to imply major work in
a *lot* of common Perl modules.

At that point I decided to turn to p5p and ask if there is any
coordinated effort relating to Perl and IPv6 going on, and if so
where. If not, is anyone but me interested in working on it? .SE is
willing to let me do at least some of it on time they're paying for.
		     Calle Dybedahl <>
     "And don't try to tell us there is no way to go but up, because the
      truth is, there is *always* more down." -- Gunn, Angel: the Series

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