verizon.net and other email grief

Fri Dec 10 20:19:05 UTC 2004

----- Original Message ----- 
From: "Roy" <garlic at garlic.com>
To: "Rich Kulawiec" <rsk at gsp.org>; <nanog at merit.edu>
Sent: Friday, December 10, 2004 2:23 PM
Subject: RE: verizon.net and other email grief

>
>
> While I can't speak to what Verizon is using, Both Exim and Postfix have
the
> very same feature called "address verification".  Its in use at a number
of
> ISPs.  My systems reject 1000's of messages every day because of
> verification failures.

i've never seen this done with postfix, but i know that exim's default
'address verification' for non-local addresses just checks that the domain
in the from is valid and that an mx record exists for it. they also have
what they call 'callout verification', which is equivalent to what is being
discussed, but the documentation makes the drawbacks painfully clear and
suggests that it only be used against hosts within the same organization.
i'm not a fan of exim, but it appears that although they've given users the
rope, they've been diligent enough to label it appropriately.

-p

---
paul galyinin