Wrong loading of zone files containing multiple nodes differing only by case

Due to the case-preserving and mostly case-insensitive nature of DNS, there are quite a few tricky edge cases that can cause problems with DNS resolvers if they can’t handle them appropriately.

Right now, it seems that IBDNS does not specify very well what happens if multiple nodes exist in a zone file, whose owner names only differ by case. Having those nodes in a zone file seems to be causing some issues at lookup time.

What should be the correct behavior, I think, is as follows.

By default, if a query is made to a name that matches multiple resource records whose owner names only differ by case, all of them shall be returned. The owner name of all of these resource records shall be altered according to the owner_case_filter setting, or returned exactly as recorded in the zone file if that setting is false. If however lookups are made case-sensitive for a given subtree, only the resource records matching the exact case shall be returned.