granitecanyon - unauthorized AXFR

[Mark.Andrews at nominum.com]

> In article <20000518202646.A966 at HAL9000.jupiter.space>,
> Maurizio Cimaschi  <mcc at iol.it> wrote:
> >On Mon, May 15, 2000 at 02:25:34PM +0000, ftheisen at my-deja.com wrote:
> >> lisafrank.net.   IN  A  24.0.163.110
> >> ; alias for the canonical names
> >> main     IN  CNAME lisafrank.net.
> >> www      IN  CNAME main
> >> ftp      IN  CNAME main
> >
> >Think you should change www & ftp records in
> >
> >www	IN	CNAME 	lisafrank.net.
> >ftp	IN	CNAME	lisafrank.net.
> >
> >AFAIK there's must be no CNAME on the right side.
> 
> Chains of CNAMEs *are* allowed.  RFC 1034 section 3.6.2 says "CNAME chains
> should be followed", and the algorithm in section 4.3.2 will do so
> automatically (when it encounters a CNAME, it simply restarts the algorithm
> using the name it points to).
> 
	Yes they must be followed if encountered but it is still not a good
	idea to deliberately generate them.  The quote above says that the
	server must handle what would otherwise be a error condition.

"Several special conditions can occur with aliases.  Multiple levels of
aliases should be avoided due to their lack of efficiency, but should
not be signalled as an error.  Alias loops and aliases which point to
non-existent names should be caught and an error condition passed back
to the client."

	Mark
--
Mark Andrews, Nominum Inc.
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at nominum.com