query re IPv6 URL format

[Brian E Carpenter]

Sadly I believe that only

> 1. Change the textual representation of IPv6 addresses. 

will work. The colons kill us.

  Brian

>- Matt Crawford said:
> 
> Brian,
> 
> I brought this up quite some time ago and there was a little
> discussion, in which you participated, but no "decision" as such that
> I recall.  Here's my original message and a summary ...
> 
> ------- Forwarded Messages
> 
> To: iesg@cnri.reston.va.us, ipng@sunroof.eng.sun.com
> From: "Matt Crawford" <crawdad@fnal.gov>
> Subject: clash between PS rfc1884 and PS rfc1783
> Date: Tue, 16 Jan 96 14:19:31 -0600
> 
> The text representation of IPv6 addresses specified in item 2 of
> section 2.2 of RFC1884:
> 
>         For example the following addresses:
> 
>              1080:0:0:0:8:800:200C:417A  a unicast address
> 	     [...]
>         may be represented as:
> 
>              1080::8:800:200C:417A       a unicast address
> 
> results in a possible ambiguity if such an IPv6 address appears in a
> URL constructed according to RFC1738 (section 3.1):
> 
>        While the syntax for the rest of the URL may vary depending on the
>        particular scheme selected, URL schemes that involve the direct use
>        of an IP-based protocol to a specified host on the Internet use a
>        common syntax for the scheme-specific data:
> 
> 	    //<user>:<password>@<host>:<port>/<url-path>
> 
> (While RFC1738 only mentions IPv4 addresses appearing as <host>, it
> will be widely presumed that IPv6 addresses may also be used.)
> 
> If the last 16-bit component of an IPv6 address used as <host> in a
> URL contains only digits 0 through 9, it may look as if a port number
> is present.  Conversely, if a port number is present and has no more
> than four digits, it will resemble a part of the IPv6 address.
> 
> 
> 
> Solutions:
> 
> 1. Change the textual representation of IPv6 addresses.
> 
> 2. Forbid the "::" abbreviation of IPv6 addresses in URLs and other
> contexts in which a port number might be appended with a colon.
> (Then counting the fields will reveal whether a port number is
> present.)
> 
> 3. Forbid the use of literal IPv6 addresses in URLs.
> 
> 4. Change the syntax of URLs.
> 
> 
> All of these have drawbacks.  I suggest that #1 is better than #2,
> and #3 and #4 are out of the question.
> _________________________________________________________
> Matt Crawford          crawdad@fnal.gov          Fermilab
>   PGP: D5 27 83 7A 25 25 7D FB  09 3C BA 33 71 C4 DA 6A
> 
> ------- Message 2
> 
> To: iesg@CNRI.Reston.VA.US, ipng@sunroof.Eng.Sun.COM
> Cc: Robert Elz <kre@munnari.OZ.AU>,
>     huitema@pax.inria.fr (Christian Huitema),
>     Brian Carpenter CERN-CN <brian@dxcoms.cern.ch>,
>     Francis Dupont	<Francis.Dupont@inria.fr>,
>     Geert Jan de Groot <GeertJan.deGroot@ripe.net>,
>     John Gardiner Myers <jgm+@CMU.EDU>
> From: "Matt Crawford" <crawdad@fnal.gov>
> Subject: Re: (IPng 1170) Re: clash between PS rfc1884 and PS rfc1783 
> In-reply-to: Your message of Wed, 17 Jan 96 14:40:05 +0100.
>              <v02120d08ad229015562c@[138.96.24.178]> 
> Date: Wed, 17 Jan 96 09:46:16 -0600
> 
> I like kre's idea of writing 32 unadorned hex digits, but it only
> works for email where there is some surrounding marker.  Dropped into
> the URL format (or typed (ugh!) at a command line, you can't tell a
> 32 digits IPv6 address from a 32 character short-form hostname.
> 
> I like even more Francis' idea of writing literal IPv6 address as
> names in ip6.int.  However, the times you'd want literal addresses
> are exactly the times you suspect DNS may not be fully operational.
> (As is the case now: ns.isi.edu. can't find ip6.int.: Server failed.)
> So the magic would have to be wired into gethostbyname() or in the
> resolver.  (Concoct a AAAA record on the spot in answer to a AAAA
> query on a name in ip6.int.)
> 
> Does the gain justify the ugliness?
> 
> Steve's suggestion of using the URL quoting mechanism (so that
> 1080::8:800:200C:417A becomes 1080%3A%3A8%3A800%3A200C%3A417A)
> works for URLs, but it starts us down a piecemeal-solution path.
> _________________________________________________________
> Matt Crawford          crawdad@fnal.gov          Fermilab
>   PGP: D5 27 83 7A 25 25 7D FB  09 3C BA 33 71 C4 DA 6A
> 
> ------- End of Forwarded Messages
>