Hello Michael,
On 02/03/2014 02:41 PM, m...@tls.msk.ru wrote:
> 3 feb 2014 г. 17:08:31 GMT+04:00, IMAP List Administration <li...@y42.org>
> wrote:
> >
> >Indeed, the problem was being caused by bug(s) in the OpenBSD
> >implementation of
> >gethostbyaddr().
>
> Care to give some more information about those bug(s) please?
apparently a large portion the DNS resolver was rewritten for OpenBSD 5.4. In
the changes for 5.4 one can find a number of bullet-items referring to the "new
resolver". I do not know why it was re-implemented.
Apparently the list of test-cases the author(s) used was not complete. In
particular, gethostbyaddr() would deliver a correct result for a "trivial"
query, i.e., if an address had a single PTR record. But gethostbyaddr() would
fail for 2 types of non-trivial configurations:
1) if a CNAME record had to be looked up in order to be able to look up the PTR
record (a mechanism used by ISPs to delegate in-arpa address-spaces that are
usually smaller than a class C subnet -- RFC2317).
2) when trying to look up addresses with several PTR records.
Case 1 was caused by not allowing a slash ("/") character in names.
There is a patch available (look at the OpenBSD "tech" list) which seems to fix
the problem.
cheers,
Rob Urban
