[ALUG] Re: MX/Zone/DNS question

[Brett Parker]

On Fri, Jan 26, 2007 at 12:37:03PM +0000, cl at isbd.net wrote:
> On Fri, Jan 26, 2007 at 09:57:44AM +0000, Brett Parker wrote:
> > On Fri, Jan 26, 2007 at 09:22:40AM +0000, MJ Ray wrote:
> > > cl at isbd.net wrote: [...]
> > > > I have Postfix on my home system (for sending mail).  If I want it to
> > > > receive mail as well what do I need to do to the zone file[s]?
> > > 
> > > Short answer: it depends how your zone and Postfix are configured.
> > > 
> > > > At BSNet (where isbd.net has its zone file) will the CNAME entry I
> > > > already have mean that mail for xxx at home.isbd.net will get sent on or
> > > > do the MX records for isbd.net catch home.isbd.net mail as well?
> > > 
> > > More likely the first than the second, but I seem to recall that some
> > > buggy mailservers handled CNAME badly.
> > 
> > Actually not buggy behaviour - an MX should always point to an A record
> > (part of the spec, IIRC), and hysterically, an A record was checked for,
> > now the order is MX -> A -> undefined evilness!
> > 
> ... but that really doesn't answer my question.  If there's an MX
> record (or MX records actually) for isbd.net does that have any
> relevance to mail for home.isbd.net?  If it *doesn't* have any effect
> then what happens to mail for home.isbd.net - will the CNAME entry
> have any effect or will the mail just get rejected as having a
> non-existent destination?

It *should* be rejected.

-- 
Brett Parker