| Subject: | Net::DNS::Resolver::Recurse and IPv6 Reverse DNS |
| Date: | Thu, 20 Aug 2015 19:08:41 +0200 |
| To: | bug-Net-DNS [...] rt.cpan.org |
| From: | Fabian Thorns <fabian [...] thorns.it> |
Dear all,
when resolving IPv6 reverse DNS with Net::DNS::Resolver::Recurse [1],
resolution for some names is stopped while following the delegations. In
all cases, Net::DNS::Resolver was able to correctly resolve the names.
For example: The lookup of 2001:4dd0:ff00::1 (a SixXS gateway) only
makes it the authoritative name server for ip6.arpa. zone. There it
stops instead of following the delegation to one of the name servers
authoritative for d.4.1.0.0.2.ip6.arpa. . I observed this behaviour for
several IP addresses, in all cases the resolution stopped at the
delegation from ip6.arpa to the next zone.
One of the counterexample I found is 2001:67c:2e8:22::c100:68b (RIPE
itself) which manages to jump over the questionable delegation. As far
as I compared the the DNS packets I didn't found any severe difference
(except for the zones and name servers of the delegation, of course). In
both cases the delegation from ip6.arpa. to the next zone did not
include an additional section. It might be a coincidence, but all
addresses for which I observed this behaviour were managed by RIPE (but
not all RIPE managed addresses show this behaviour). In case it helps I
could provide more examples and/or debugging output for both cases.
Sorry for not being able to provide a bug fix or detailed information
where in the code this issue might be. I did my best looking at the DNS
packets, but, unfortunately, I didn't observed any major difference
there. If there are any patches to test I'd love to do so.
Best regards and thank you for your work on Net::DNS!
Fabian
[1] Net-DNS-1.01: Recurse.pm 1339 2015-04-16 13:01:17Z; Perl v5.20.2