Also note, that a lot of big ISPs don't accept mails for their domains from
their domains from foreign servers...
Example:
You customer has user1@??? forwarding to user1@???.
Now user2@??? want to send a mail to user1@??? .
That gets forwarded to user1@???.
The AOL server receiving this mail sees a mail for user1@??? from
user2@??? but from a non-AOL-server.
I am not sure about AOL, but other providers will directly move that message
into SPAM or even reject it.
GMX for example does so.
SRS helps you there, as the MAIL-FROM-header gets rewritten to show YOUR
domain, which AOL will accept.
Regards,
Steffen
> -----Ursprüngliche Nachricht-----
> Von: exim-users-bounces@??? [mailto:exim-users-
> bounces@???] Im Auftrag von John Traweek
> Gesendet: Montag, 9. Mai 2011 13:59
> An: exim-users@???
> Betreff: [exim] Virtual Forward To's Eliminate NDR's
>
> We allow our customers to set up vanity email addresses, which we market
> as email for life accounts. The accounts are strictly forwarding
accounts, so
> there is not a "mailbox" so to speak. Mail comes in, and is forwarded on
to a
> permanent account. So for example, a customer may wish to have an
> account user1@??? forward to user2@???.
> If two years from now, the customer changes ISP's from AOL to a Yahoo
> account, he or she would simply access our system and change the forward
> to user2@???.
>
> We have had this product in place for about ten years using a multitude of
> systems, including Barracuda gateways, a group of load balanced servers to
> perform the forwarding mechanism and another group of servers to perform
> the outbound delivery.
>
> I am looking at moving everything to a couple of servers running Exim4,
> SpamAssassin, ClamAV, and MySQL using virtual users. I am an exim newbie
> and Linux newbie, but have managed to get a test box set up on Ubuntu 8.04
> LTS and everything seems to be running great.
>
> One of the problems we have with our old setup is that people will let
their
> forward to address go bad and never update it. So when the message
finally
> gets to the outbound MTA's destined to one of these bad forward to's an
> NDR is generated and sent back to the sender. Not so good... It's a
perfect
> back spattering spam machine.
>
> One of the nice things I have noticed about Exim is that out of the box
with
> the way I have it set up it will verify the forward to domain. So for
example, I
> have virtualuser@??? forwarding to user@???.
> During the initial receiving transaction Exim will verify baddomain.com.
If it
> doesn't exist it will 550 the transaction and no NDR from my server.
Great!
>
> So my question is can it also verify the RCPT TO of the forwarding address
> during the original transaction as well? This would issue a transaction
> response back to the connecting MTA, thus preventing further
> NDRs being generated?
>
> If this is possible, what will happen with non permanent failures, such as
> 400's, ie mail box full etc? Will those be issued back to the originator
during
> the transaction, so the responsibility is put back on the originating MTA
to
> retry the transmission?
>
> TIA
>
>
>
> ________________________________
>
>
> John Traweek
> Executive Director, Information Technology Proud PCI Associate for 14
years
> PCI: the data company
> Heritage Square
> 4835 LBJ Freeway, Suite 1100
> Dallas, TX 75244
> 214.530.0394
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