In message <[email protected]>, John Levine writes:
>
> A friend* wonders about the SMTP treatment of addresses in TLDs.
> Historically there have been a smattering of such addresses, most
> famously n...@ai, and there are 21 TLDs with MX records, but spot
> checking shows that most appear to be config mistakes, with the MTAs
> not actually accepting mail to postmas...@tld.
>
> If ICANN does what they claim they're going to do and starts selling
> thousands of new TLDs, we're likely to see a lot more dotless
> addresses. b...@aol, anyone?
>
> As best I understand it, the prose description of addresses in 2821
> allowed TLDs in addresses, but the ABNF didn't. In 5321 the ABNF
> changed to match the prose. Although the DNS allows you to put a dot
> at the end of a domain name to make it clear that it's an absolute
> address, SMTP has never allowed that.
>
> My impression is that in the real world, mail addressed to
> postmas...@va is far more likely to be rewritten to
> [email protected] than delivered to the Vatican (which, as it
> happens, will accept it.) Mail addressed to postma...@va. with a dot
> isn't valid under 821, 2821, or 5321, so some MTAs accept it, some
> reject it.
>
> Is the current situation with TLDs deliberate, or was the change in
> 5321 just aesthetic tidying up? Is there any reason not to permit a
> trailing dot in 5321-bis to bring it in line with DNS rules?
>
> Regards,
> John Levine, [email protected], Primary Perpetrator of "The Internet for Dummies
> ",
> Information Superhighwayman wanna-be, http://www.johnlevine.com, ex-Mayor
> "More Wiener schnitzel, please", said Tom, revealingly.
>
> * - no, really
Dotless hostnames are in the local namespace and can *never*
be made to work *reliably* in a global context.
Note the use of non-heirachical names is undoing the changes
introduced by RFC 921 and will introduce problems RFC 921
was trying to remove/prevent.
Mark
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: [email protected]
