[SLL] Greylisting downsides: Solutions?

[Jeremy C. Reed]

On Tue, 12 Jun 2007, Glenn Stone wrote:

> So I was just doing something on a major car-rental company's website, and I
> said to myself, "That's gonna generate an email."  So I went into Postgrey's
> whitelist, added what I *thought* should be the appropriate domain,
> reloaded, hit SUBMIT, and.... nothing.  Checked /var/log/mail.log, there's
> the attempt, but it HELOed as... who??  Turns out it was a host owned by
> Postini, who is apparently handling Not Exactly's email for them.  (Hertz,
> for what it's worth, whoever is running their email servers actually have
> them HELO'ing as hertz.com.  Win!)  

<snip>

> (SPF would be nice, but very few people, including said
> rent-a-car company, implement it.) 

I don't use Postgrey, but I assume from above you can whitelist based on 
the HELO.

But you mention SPF. And the SPF record for them lists a bunch of IPs -- 
what about whitelisting based on that instead?

Somewhere I saw a script that reads SPF records and creates a lists of IPs 
(or networks) ready to add to a whitelist.

I have done that some to prepopulate some of my whitelists to bypass my 
spamd greylisting.

  Jeremy C. Reed