Renaud Allard wrote:
>
> Adam Stephens wrote:
>> Similarly, section 3.6 requires all domain names used in SMTP
>> transactions to be 'resolvable, fully-qualified, domain names'.
>
>
> Just quoting section 3.6 of RFC2821:
> - The domain name given in the EHLO command MUST BE either a primary
> host name (a domain name that resolves to an A RR) or, if the host
> has no name, an address literal as described in section 4.1.1.1.
>
>
> How many people here do filtering based on "resolvability" of the HELO
> argument? I just wonder, I think this should be very effective at
> filtering spam, but would reject way too much ham.
>
For many years now...
But it is a 'demerit point' integer we look at later with others.
As you note - many major ISP's don't read or heed no steenkin' RFC's.
Still - one more twig on the fire if other things earn demerits as well...
Does help...
Bill