Re: block numeric MX

[Craig Sanders <cas@xxxxxxxxxx>]

On Sun, Jan 02, 2005 at 08:34:39AM -0500, Chad M Stewart wrote:
> On Dec 31, 2004, at 8:10 PM, Craig Sanders wrote:
> >it's not misleading. it's USEFUL to be able to block mail from
> >domains where the MX record resolves to, e.g., an RFC-1618 private
> >address, or 127.0.0.1.
>
> Actually MX records are NOT allowed to point to IPs.

i know that.  i said "resolve to".   you're talking about something completely
different.


> I'd argue that any MX that resolves to just an IP is bogus.           

"resolve to" means "after all lookups have been done.  i.e. MX lookup, then A
lookup.  *ALL* valid MX records resolve to an IP address, otherwise they are
no use.


> MX records are also not allowed to point to CNAMEs. 

yes.

> Basically MX entries are allowed to resolve to A records only AFAIK.

not exactly.

MX records may not contain an IP address.  they must contain a hostname that
points to an A record and resolves to an IP address. 

craig

-- 
craig sanders <cas@xxxxxxxxxx>           (part time cyborg)

my postfix scripts are at http://taz.net.au/postfix/scripts/