Subject: [certid] wrt domain names vs hostnames (was: Re: DC should be MUST NOT)

From: =JeffH <[email-masked]>
Date: Fri, 02 Jul 2010 22:58:24 -0700

Martin Rex <[email-masked]> declared..
 >
 > Paul Hoffman wrote:
 >>
 >> If you feel that way, fine. We have historically seen deployed PKIX
 >> implementations that got the order wrong because they had no certs
 >> to test with. I do not hold it against someone to get the order wrong,
 >> particularly because all of the text examples in RFC 5280 say
 >> "dc=example,dc=com".
 >
 > You're right on the spot -- all of the DC= examples in rfc-5280 are
 > purely about >>domain name<<.  There is also a server mentioned
 > "ldap.example.com", but there is not a single example in rfc-5280
 > that puts a >>hostname<< into a DC component.

However, there is a explicit, and to-some-degree-formally acknowledged, 
disagreement over whether there are salient differences (today) between 
"hostnames" and "domain names".

I just want to point this out because I only recently became aware of it while 
working on -server-id-check- and -strict-transport-sec- and I think it is 
something many of us should be aware of, however I don't think re-opening such 
a discussion is appropriate for the certid@ list.

The acknowledged disagreement is buried in RFC3490 [1] in its terminology 
section (emphasis added)..

    [STD13] talks about "domain names" and "host names", but many people
    use the terms interchangeably.  Further, because [STD13] was not
    terribly clear,

 >>> many people who are sure they know the exact  <<<
 >>> definitions of each of these terms disagree on the definitions.  <<<

    In this document the term "domain name" is used in general.  This
    document explicitly cites [STD3] whenever referring to the host name
    syntax restrictions defined therein.

A significant portion of the discussion that led to the above posture is 
documented in this thread 
<http://www.ops.ietf.org/lists/idn/idn.2001/threads.html#02989> (from back in 
2001) rooted here...

   [idn] hostname history hell
   http://www.ops.ietf.org/lists/idn/idn.2001/msg02989.html

And here's Patrik Fältström's contribution/statement to the thread which seems 
to presage the  above-cited rfc3490 language..

   http://www.ops.ietf.org/lists/idn/idn.2001/msg03048.html

=JeffH

[1] "Internationalizing Domain Names in Applications (IDNA)"  RFC3490
http://www.ietf.org/rfc/rfc3490.txt