Re: HELO vs. MAIL FROM

[email protected] wrote:
> 
> On Wed, Oct 22, 2003 at 02:49:38PM -0400, Alan DeKok wrote:
> >
> >   We look at the domain for the host name, and ask that domain about
> > the IP address which claimed to be a host in that domain.
> ...
> >   We strip off the machine name, and only the machine name.
> >
> >   e.g. I have a machine 'giles.striker.ottawa.on.ca'.  I've had
> > bounces from idiot mailers, because they claim that 'ottawa.on.ca'
> > doesn't have an MX, and doesn't know about 'striker.ottawa.on.ca'.
> >
> >   We can assume that the name in the EHLO/HELO is a host name,
> > followed by a domain.  We can make NO assumptions about that domain.
> 
> So we can assume that the EHLO name consists of at least three
> components?    host.domain.com ?

Bad assumption. The host name and the domain name may be the same. Is
Sales.Example.com a domain name or a hostname or both? How about
customer01.relays.example.net?

> Or just two?   Would it be allowed to name my relay just
> danisch.de ? Many domains give their domain name an A record
> and have web servers at the domain name without "www."

Allowed. people do it already.

> If the machine is named like danisch.de (=domain name without host
> name) the lookup would fail in general.

Then the lookup is wrong.

> So as a general requirement for things to work we'd state that
> a EHLO name must always be of the form
> 
>   hostname.DOMAINWHERETOLOOK
> 
> where hostname is exactly one component and
> DOMAINWHERETOLOOK consists of at least two?

Telling domain name owners how to manage their namespace isn't going
work. Forget the concept of a host component and treat the HELO
parameter as a domain name.


Raymond S Brand