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Length of labels (RE: [idn] IURL vs URL, IDNS name vs DNS name)
- To: Jonathan Rosenne <rosenne@qsm.co.il>, idn@ops.ietf.org
- Subject: Length of labels (RE: [idn] IURL vs URL, IDNS name vs DNS name)
- From: Harald Tveit Alvestrand <Harald@Alvestrand.no>
- Date: Tue, 15 Feb 2000 00:05:55 +0100
- Delivery-date: Mon, 14 Feb 2000 15:17:34 -0800
- Envelope-to: idn-data@psg.com
At 19:00 11.02.00 +0200, Jonathan Rosenne wrote:
>The UCS could be encoded using A-Z 0-9. On average each non-ASCII character
>would require 3 to 4 characters. All we need to change is to allow longer
>names in DNS and to provide a viewer which decodes these creatures back to
>UCS or the local code page.
Unfortunately the limit of 63 octets per domain name component is enshrined
in a 6-bit length field in RFC 1035, section 4.1.4 (the 2 upper bits are
used as a flag to indicate pointers or "something-elses"), so "all we need
to change" to get this length increased is every single piece of DNS
software on the planet.
Not that we might not come to that anyway...
Harald
--
Harald Tveit Alvestrand, EDB Maxware, Norway
Harald.Alvestrand@edb.maxware.no