On 2003-12-21 10:52:22 -0500, Keith C. Ivey wrote:
> Guillaume Filion <[EMAIL PROTECTED]> wrote:
> 
> > It might be simpler to make an SMTP connection to the MX RR of
> > the sender's domain, and maibe even do a MAIL FROM: <>, RCPT TO:
> > $senderAddress to do a simple address check.
> > 
> > If the sender's SMTP server is not available, we can return a
> > temporary error code.
> 
> Aagh, no!  That's what Verizon seems to be doing nowadays,

Hasn't somebody here posted a plugin to do this recently? Anyway, at
least exim has been able to do this for some time, and other MTAs are
following.

> and it's leading to larger mail queues everywhere.

Noticeable? Sure it may take a few seconds to verify the email address
that way, but other common tests (esp. DNS lookups) also take a lot of
time. 

What I'm more concerned about is that this is will probably help only
for a short time: Then the spammers will switch to using existent
addresses.


> And what happens if the SMTP server you're trying to connect to wants
> to do the same thing?

Nothing. Because of the MAIL FROM: <>, the other party can't do the
reverse check.

        hp

-- 
   _  | Peter J. Holzer    | In this vale
|_|_) | Sysadmin WSR       | Of toil and sin
| |   | [EMAIL PROTECTED]         | Your head grows bald
__/   | http://www.hjp.at/ | But not your chin.           -- Burma Shave

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