Re: [exim] "sender verify defer" although no "verify sender"

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Author: Giuliano Gavazzi
Date:  
To: Marten Lehmann
CC: exim-users
Subject: Re: [exim] "sender verify defer" although no "verify sender"
At 5:03 pm +0100 2004/11/23, Marten Lehmann wrote:
>Hello,
>
>>If verify=sender doesn't succeed on your server then it won't succeed on
>>the recipient's server either.
>
>yes, for sure. But most simple clients don't check for errors. They
>just send an email to a recipient, that really exists. But if the
>mailserver refuses their email because of a wrong sender address,
>neither they receive an error message nor the recipient receives the
>email, although there's no reason why the email is not received.



I do not see why they would not receive an error in the case you
illustrated: an email submitted by one of your clients with an
incorrect envelope sender. Or better: I do not see it, unless your
server is set to accept relaying for them *without* doing a sender
verify. So, if you *do* want them to receive an error (this would be
directly as a dialog of some sort from their email client) do *not*
accept email from them (at the mail from stage I'd say) if the sender
address cannot be verified, just remember to set "message" to
something clear enough. If you instead keep on accepting email with
undeliverable envelope senders, when an incorrectly labeled email is
rejected by a remote server you will not be able to return the bounce
(generated by you) to you sending client, and your queue will be full
of frozen messages.

For one my server would not accept an email from you with an
incorrect envelope sender.

>
>But anyway: My problem is, that the sender verify seems to be done
>although exim isn't explicitly told to do it. So how can I really
>disable it, or what is causing exim to do the check although it's
>not in the ACL?
>


Sorry, but what is your perception of your problem is not relevant
when it clashes with the well functioning of the email system. It
would not be the first time that no advice is given that might lead
to a misconfiguration...

Now that both Tony and I have taken so much time to write our replies
please stop asking that same question and change your configuration,
as in:

Before:

   accept  hosts         = +relay_from_hosts


accept authenticated = *


After:


   accept  hosts         = +relay_from_hosts
           endpass
           message       = Wrong sender address: $sender_address.\n
                           Please verify your configuration.
           verify        = sender


   accept  authenticated = *
           endpass
           message       = Wrong sender address: $sender_address.\n
                           Please verify your configuration.
           verify        = sender



I think these should work.

Giuliano