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Re: domain name definition in RFC2821

2006-04-22 01:29:46
On Sat, 22 Apr 2006 00:12:17 PDT, "william(at)" said:
On Sat, 22 Apr 2006 Valdis(_dot_)Kletnieks(_at_)vt(_dot_)edu wrote:
Can you give an example of a "single-component domain name" that would *not*
be flagged as a failure to canonalize to a FQDN?

Are there any e-mail addresses that *work* (or even could *potentially* 
of the form 'userid(_at_)com' or 'userid(_at_)net' or 
'some(_dot_)full(_dot_)name(_at_)to' or anything
else like that?

postmaster(_at_)ws ?

ws.                     21600   IN      MX      10

Gaak.  I hope that's not a wildcard MX. ;)

A 4AM re-reading of 2821 seems to indicate that's a *legal* setup.  But
I suspect there are *so* many software packages that will try to convert
'@ws' to a FQDN at message submission time as per 2821, section 6.3:

   The following changes to a message being processed MAY be applied
   when necessary by an originating SMTP server, or one used as the
   target of SMTP as an initial posting protocol:
   -  Addition of a message-id field when none appears

   -  Addition of a date, time or time zone when none appears

   -  Correction of addresses to proper FQDN format

(For instance, on my Fedora Linux box, the default resolv.conf setting of
'options ndots:1' means that 'ws' will be canonalized to a FQDN, while
'ws.' will behave the way Yuri apparently expects 'ws' to work.  Now
try to explain to your average end user why 'postmaster(_at_)ws' and
'postmaster(_at_)ws(_dot_)' do different things....

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