[Postfixbuch-users] PTR und CNAME zulässig?

[Ruben Rögels]

Am 07.10.2011 13:05, schrieb Mathias Jeschke:
> Am 07.10.2011 12:57, schrieb Andreas Schulze:
> 
>>> laut RFC darf ein PTR record nicht auf einen CNAME verweisen.
>> hast Du die konkrete Stelle zum nachlesen parat ?
> 
> Zitat (RFC 2181):
> 
> "10.2. PTR records
> 
>    Confusion about canonical names has lead to a belief that a PTR
>    record should have exactly one RR in its RRSet.  This is incorrect,
>    the relevant section of RFC1034 (section 3.6.2) indicates that the
>    value of a PTR record should be a canonical name.  That is, it should
>    not be an alias.  There is no implication in that section that only
>    one PTR record is permitted for a name.  No such restriction should
>    be inferred.
> 
>    Note that while the value of a PTR record must not be an alias, there
>    is no requirement that the process of resolving a PTR record not
>    encounter any aliases.  The label that is being looked up for a PTR
>    value might have a CNAME record.  That is, it might be an alias.  The
>    value of that CNAME RR, if not another alias, which it should not be,
>    will give the location where the PTR record is found.  That record
>    gives the result of the PTR type lookup.  This final result, the
>    value of the PTR RR, is the label which must not be an alias."
> 
> Wobei "should not be" als DARF NICHT (IIRC) übersetzt wird.
> 
> Gruß,
> Mathias


Ist auch alles definiert:

http://www.ietf.org/rfc/rfc2119.txt

;-)


Gruß,
Ruben