On Wed, 2 Jan 2019, Brian Dickson wrote:
Let's assume for the purposes of argument that we have a DNS server that
knows how to translate between A-labels an U-labels. Then I invent this
DNS record
Is it the case that you have a bunch of labels that you want to have
treated as equivalent, and that at the terminus of any given FQDN involving
a sequence of equivalence-sets of labels, there is a single "canonical"
owner name for all the RRtypes/RRsets?
Basically yes, it's the IDN version of ASCII upper/lower case equivalence.
If you have a label ABCD in your zone, it'll match abcd and Abcd and 14
other upper-lower combinations.
This is to use DNAMEs for all of the variants, with all names being
letter-digit-hyphen format (a-label?), so for i18n stuff, xn--* format.
Unfortunately this is a WKBI for multiple reasons:
* DNAME only maps names below it, not the name itself. This is why this
approach completely failed in the .CAT TLD to try and map accented to
unaccented names.
* DNAME only maps one name at a time, but a name can have many variants
and there can be variants at every level, e.g., if a name is FOO.BAR,
there's 8 possible variants for each label.
* DNAME synthesized names are not equivalent to the original, particularly
for mail since MX to CNAME is not allowed and the rule is spottily
followed.
Taiwan has a DNAME to map the simplified .台湾 to .台灣. It sort of
works.
$ dig xn--kprw13d. dname
;; ANSWER SECTION:
xn--kprw13d. 3600 IN DNAME xn--kpry57d.
This is to use authority-size zone file references, and pull in identical
zone files by reference, rather than keep the parallel zones as separately
maintained entities.
That's not exactly a WKBI, but it only solves a small part of the problem.
You can use it to map equivalent zones line foo.ngo and foo.ong, but it
doesn't handle variant names within the zone. I use it in my DNS toaster
for a user who has a lot of vanity zones and want them all to point to the
same place.
Regards,
John Levine, jo...@taugh.com, Taughannock Networks, Trumansburg NY
Please consider the environment before reading this e-mail. https://jl.ly
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