Antw: RE: [Postfixbuch-users] RFC-Konformität zu MX und CNAME? [Nachtrag]

[Uwe Hering]

Aber:

RFC2821:

3.6 Domains

   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 A RRs (as discussed in section 5) are
   permitted, as are CNAME RRs whose targets can be resolved, in turn,
   to MX or A RRs.

und 5. Address Resolution and Mail Handling

...The lookup first attempts to locate an MX
   record associated with the name.  If a CNAME record is found instead,
   the resulting name is processed as if it were the initial name.

und HISTORY-File Postfix (2.1.5):

Performance: RFC 2821 blesses the use of CNAME domain names
        in MAIL FROM and RCPT TO. Not having to expand CNAME domain
        names speeds things up a bit.  File:  smtp/smtp_proto.c.


Uwe

>>> mlists at eomis.de 13.05.05 14.16 >>>
Hallo,

> > Schaut Euch das bitte einmal an. Der findet eine IP für 
> > mail.cph-hotels.com, aber empfielt, dorthin KEINE MAIL 
> auszuliefern, 
> > weil mail.cph-hotels.com ein CNAME ist.
> > 
> > Ist das nicht verrückt?
> 
> Nein.
> 
http://www.faqs.org/rfcs/rfc1912.html

Don't use CNAMEs in combination with RRs which point to other names
  like MX, CNAME, PTR and NS.  (PTR is an exception if you want to
  implement classless in-addr delegation.)  For example, this is
  strongly discouraged:

          podunk.xx.      IN      MX      mailhost
          mailhost        IN      CNAME   mary
          mary            IN      A       1.2.3.4


Auweia ....

dann hab Du mal ein herzliches Dank. Denn ich hab das nicht gewusst und
auch nicht gefunden.

Wieder einmal bestätigt sich, dass die Liste hier ein wahrer Schatz ist.

Danke schön

Daniel


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