(unknown charset) Re: bind timeouts

On Tue, May 18, 2004 at 07:23:52AM -0700 I heard the voice of
Randy Bush, and lo! it spake thus:
> >> RFC974 says:
> >>     There is one other special case.  If the response contains an
> >>     answer which is a CNAME RR, it indicates that REMOTE is actually
> >>     an alias for some other domain name. The query should be repeated
> >>     with the canonical domain name.
> > 
> > That covers the intial lookup, meaning that a CNAME pointing to an MX is
> > legal.
> 
> no.  it means an MX referring to a CNAME which resolves to an A

Not by my reading.

    The first step for the mailer at LOCAL is to issue a query for MX
    RRs for REMOTE.

    [...]

    If the response contains an answer which is a CNAME RR, it
    indicates that REMOTE is actually an alias for some other domain
    name. The query should be repeated with the canonical domain name.

which covers the case:

foo     IN      CNAME   bar
bar     IN      MX  10  mail
mail    IN      A   127.0.0.1


not the case:

foo     IN      MX  10  bar
bar     IN      CNAME   mail

                           ----------------

But, as I came across in a completely seperate quest (today is Bizarre
Coincidence Day, boys and girls!), see RFC2181 §10.3:

    The domain name used as the value of a NS resource record, or part
    of the value of a MX resource record must not be an alias.

Of course, 2181 is a _Proposed_ Standard, for whatever value you may
choose to assign to that classification.



-- 
Matthew Fuller     (MF4839)   |  fullermd_at_over-yonder.net
Systems/Network Administrator |  http://www.over-yonder.net/~fullermd/

"The only reason I'm burning my candle at both ends, is because I
      haven't figured out how to light the middle yet"