At 13:37 +0200 10/20/05, Harald Tveit Alvestrand wrote:
--On torsdag, oktober 20, 2005 21:17:34 +1000 Mark Andrews <Mark_Andrews@isc.org> wrote:2) A different conversation led to the (to me) surprising conclusion that there is no IETF document that conclusively states that top level domains shouldn't be all numeric. I think this is an appropriate thing for the IETF to state in a BCP, since 4-component all-numeric domain names are hard to tell from IP addresses - a technical consideration in many protocols.RFC 1123 comes close. If a dotted-decimal number can be entered without such identifying delimiters, then a full syntactic check must be made, because a segment of a host domain name is now allowed to begin with a digit and could legally be entirely numeric (see Section 6.1.2.4). However, a valid host name can never have the dotted-decimal form #.#.#.#, since at least the highest-level component label will be alphabetic.Yep - but I'm betting that this will be ruled non-normative eventually, because some people want IDNs in TLDs, and Punycode uses numbers in its encoding.
It's a long leap from "must be alphabetic" to "can be all-numeric" - but I'd prefer to have something explicit somewhere, so that we don't end up there by accident. I *think* it's uncontroversial. But better safe than sorry.
As many of us have said before, 1123 refers to host names, not domain names. (Host names are a subset of domain names.) In an NS and MX record, you want a host name, not necessarily so in a RRSIG record.
I disagree with the suggestion to bar all-numeric names. Mostly because I don't like "rules" that are unnecessary. I don't see the necessity of such a restriction.
I am not arguing against what 1123 says. From what I understand, if a domain name represents a host, then a numeric label can cause confusion for an application like telnet (to pick on an old, tired horse). There is a necessity for that, even if there is a "newer version [of the application] out there."
But in general, I don't see the harm of an all numeric label, even a TLD. -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Edward Lewis +1-571-434-5468 NeuStar True story: Only a routing "expert" would fly London->Minneapolis->Dallas->Minneapolis to get home from a conference. (Cities changed to protect his identity.) -- to unsubscribe send a message to namedroppers-request@ops.ietf.org with the word 'unsubscribe' in a single line as the message text body. archive: <http://ops.ietf.org/lists/namedroppers/>