Other communities have other needs. I've been told that some communities use a set of letters that are currently encoded in two different ranges of the Unicode space (e.g. Latin and Cyrillic). Today, my idea is that these communities can "occupy" their "own" part of the DNS space, for example a .tld or a .2ld.tld.
If by "community" you mean users of a certain language / culture group within a geographic region, yes. In fact, they already do. The Japanese already "occupy" .jp, Korean .kr, Chinese in PRC .cn, Chinese in Taiwan .tw, Chinese in Singapore .sg, etc.
I'm not sure what you are proposing here - are you saying to allocate new TLDs for each "community"?
They can publish the rules that they enforce in their registries, ...
They already do. The rules are just not in a machine readable format, and John has already made the case against standardizing language tables, let alone other rules that may not be character-based (imagine the .th registry saying, allow both Thai and Latin digits, but not both in the same label/domain).
and then the browsers can either allow any character sequence in those labels or check them to see if the rules were indeed followed.
I'd vote against browsers trying to enforce rules set by various registries. This is the sort of thing you'd build into a specialized tool (as you mentioned) but not in a general application.
Of course, it is much harder to come up with and enforce rules in a "global" TLD like .com.
Don't forget countries who choose to honour multiple cultures within their society - .PL allows many different tables, including Cyrillic (but does not allow mixing of Cyrillic and Latin scripts, see Andrzej Bartosiewicz's draft.
As a result, the browsers may simply blacklist .com in its entirety.
It looks like a reasonable interim solution, but I'm worried about whether .com can actually get off the list. Unlike DNSBL, if the list is hardcoded or statically included in the installation package, it's going to be difficult to get off that list.
Come to think of it, as an off-IETF solution, maintaining an IDNBL of sorts might be a good idea. I know, it didn't really work for mail abuses, the landscape is quite different for the problem at hand though. The IDNBL can ban an entire zone based on the reasoning that the zone administrator has shown to be negligent (".com"), or ban individual domains of known phishers, and can even be used to implement character blacklists instead of having them hard wired in the browser.
Or maybe .com will eventually figure out some rules and actually enforce them in the 2LDs, so that the browsers don't have to check the 2LDs.
I'm hopeful that this will happen.
Indeed, in a perfect world, .com would even enforce rules in 3LDs, 4LDs, etc, so that browsers would not have to check those either.
It's not enforceable in 3LD and beyond. period.
wil.
