[UA-discuss] More from Ram Mohan on ICANN's further commitment to Universal Acceptance

John Levine john.levine at standcore.com
Tue Dec 25 21:58:20 UTC 2018

In article <2eb428e5-ed29-a914-23e3-7889b427b69d at ix.netcom.com> you write:
>What about "www." being an optional subdomain?
>How are the techniques used to handle this different from having an IDN 

I think it's pretty safe to assume that foo.com and www.foo.com are in
the same language, and if one redirects to the other, nobody will be
confused.  Even so, getting it to work right is not totally trivial.
The two names need their own SSL certificates, or if there's one cert
it has to be validated for both names.  If the site uses cookies as
most do to manage site logins or user options, it has to be sure the
cookies for the two names are kept in sync or all forced to one of the

None of this is terribly hard, but it's not automatic either.

>Yes, I did note the passage on language negotiation, but how is that 
>different from sites that can be accessed via ccTLDs in addition to a 
>domain name in a gTLD. That's a pattern typical for many global 

Same answer, except that if one name isn't a subdomain of the other,
the login and option cookie problems are a lot harder.

>How are any of these issues materially different from offering your site 
>with multiple localized names?

The point, which I apparently wrongly thought was obvious, is that none
of this multi-name stuff works automatically, and telling people "just
add a bunch of IDN names and EAI addresses" is not going to end well.



>PS: some non-European scripts can have variants that work similar to 
>case-equivalence. If you want to institute loose matching of e-mail 
>usernames based on them, you'd have to roll your own -

Yes, people who are working about EAI are aware of the way that local
part matching works.  Since every mail system already has its own
loose matching rules, it's not a new problem but it's not one that
anyone has thought much about for EAI mail addresses.  I can
definitely tell you that without loose address matching that matches
user expectations, whatever they are, your customers will hate you and
decide that your system is unusable.

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