Re: [exim] Rejecting unknown users at RCPT time (poor man's …

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Author: Dave Evans
Date:  
To: exim-users
Subject: Re: [exim] Rejecting unknown users at RCPT time (poor man's way)
On Sat, Jul 08, 2006 at 06:53:38PM -0400, My BSD wrote:
>     Mail to a non-existent user in a domain is accepted if the user
>     exists in one of the other local domains.  How to tighten it up to
>     reject by local_part@domain?


The generic answer is: ensure your routers do not accept mail for non-existent
users, then use "verify = recipient" in your acl_smtp_rcpt.

To be more specific though we'd have to know more about your setup. Does the
box in question have any way of knowing which users (in which domains) exist
and which do not?

For example, I think you mentioned that the mail gets passed to another box
(like a smart host); if it's the case that that /other/ box knows which
addresses are valid and which are not, then the answer may be to have this
first box do callouts to the second (verify = recipient/callout...).

If on the other hand this first box has its own way of knowing what's valid
and what's not (e.g. one file per domain, each containing a list of users in
that domain) then you could use that source of data to ensure that your
routers only accept recipients who exist. But if you want us to help with that,
you'd need to tell us more about what that source of data is and how it works.

--
Dave Evans
Power Internet

PGP key: http://powernet.co.uk/~davide/pgpkey