[Cialug] MTA HELO

[Paul Gray]

On 01/12/2014 12:35 PM, Kevin Smith wrote:
> #1 It's not A FQDN. Something like "cq1023". There is no attempt to resolve
> the domain. It just has to correct syntax.

No. "cq1023" would be considered a local alias, and not a valid domain.

>From the previously-cited RFC section:

   The domain name, as described in this document and in RFC 1035 [2],
   is the entire, fully-qualified name (often referred to as an "FQDN").
   A domain name that is not in FQDN form is no more than a local alias.
   Local aliases MUST NOT appear in any SMTP transaction.


   Only resolvable, fully-qualified domain names (FQDNs) are permitted
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   when domain names are used in SMTP.  In other words, names that can
   be resolved to MX RRs or address (i.e., A or AAAA) RRs (as discussed
   in Section 5) are permitted, as are CNAME RRs whose targets can be
   resolved, in turn, to MX or address RRs.  Local nicknames or
   unqualified names MUST NOT be used.  There are two exceptions to the
   rule requiring FQDNs:

By the clause emphasized above, the noyb.foo would also be invalid.

-PG