Additionally the rules have not changed. "preferred syntax" means just that "preferred syntax". It is not "required syntax". It was guidance for what is likely to be usable. Underscore also turned out to be usable especially as a way to differentiate hostnames from other types of names that are stored in the DNS.
UTF8 strings can be stored in the DNS. The case of a-z and A-Z is not always preserved. Lookups of using UTF8 strings are insensitive to a-z and A-Z. The presentation format of UTF8 strings in master files is all ascii using DNS escaping conventions. Similar things can be said about other 8 bit character sets when used in the DNS, In message <CAPt1N1=xlyvxtmsckclikqsqkanyaf04bxo6vtr1nvs10nj...@mail.gmail.com> , Ted Lemon writes: > > The document I mentioned updates RFC 1034. That's how we do things in the > IETF! > > On Thu, Apr 7, 2016 at 11:29 PM, Adrien de Croy <adr...@qbik.com> wrote: > > > yeah, paragraph 2 of that section is what I quoted as at odds with > > 1034/1035. > > > > I've been reading this stuff all day.... > > > > Looks like 1034/1035 should be obsoleted. > > > > Thankfully not many people nowadays need to write DNS resolvers. > > > > Adrien > > > > ------ Original Message ------ > > From: "Ted Lemon" <mel...@fugue.com> > > To: "Adrien de Croy" <adr...@qbik.com> > > Cc: "dnsop@ietf.org" <dnsop@ietf.org> > > Sent: 8/04/2016 2:24:33 p.m. > > Subject: Re: [DNSOP] hostnames vs domain names vs RFC1034/1035 vs RFC2818 > > vs Wikipedia etc > > > > > > Have you read the rest of the documents? E.g.,: > > > > https://tools.ietf.org/html/rfc2181#section-11 > > > > On Thu, Apr 7, 2016 at 11:21 PM, Adrien de Croy <adr...@qbik.com> wrote: > > > >> > >> > >> ------ Original Message ------ > >> From: "Ted Lemon" <mel...@fugue.com> > >> > >> > >> <domain> ::= <subdomain> | " " > >>> > >>> <subdomain> ::= <label> | <subdomain> "." <label> > >>> > >>> <label> ::= <letter> [ [ <ldh-str> ] <let-dig> ] > >>> > >>> <ldh-str> ::= <let-dig-hyp> | <let-dig-hyp> <ldh-str> > >>> > >>> <let-dig-hyp> ::= <let-dig> | "-" > >>> > >>> <let-dig> ::= <letter> | <digit> > >>> > >>> <letter> ::= any one of the 52 alphabetic characters A through Z in > >>> upper case and a through z in lower case > >>> > >>> <digit> ::= any one of the ten digits 0 through 9 > >>> > >>> > >>> if this was a BNF production only for hostnames, why call it <domain>, > >> <label> etc. > >> > >> There's no other BNF for domain name in the spec. > >> > >> Adrien > >> > >> > >> > >>> > >>> > > -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
