Re: [Exim] Redirecting SMTP session to different server base…

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Author: David Woodhouse
Date:  
To: Patrick Starrenburg
CC: exim-users
Subject: Re: [Exim] Redirecting SMTP session to different server based on RCPT address
patrick-sender-8d20fc@??? said:
> based on a lookup of the RCPT address (most likely LDAP against MS
> Exchange) the MTA could *redirect* the SMTP communication to another
> SMTP server. So MX records for domain point to, say, server
> mx.headquarters.company.com which during the SMTP coversation tells
> (bounces) the calling MTA to another MTA at, say, mx.subsidiary.company
> .com which is located elsewhere in the world.


As others have told you, this can't be done -- and even if it _could_ be
done, it'd need to be done at headquarters, and if you could get sane
policies installed at HQ you wouldn't be requesting this anyway, would oyu?

AIUI you want the sender to connect _directly_ to your own servers for two
reasons:
    1. You want to do RBL checking.
    2. You want to reject the mail and not have to bounce it.


You can achieve both -- assuming your HQ's MTA does manage to put the IP
address of the host from which it received the message into its Received:
headers, you can write a local_scan() function which does all appropriate
RBL checking on that IP address.

You can also then reject the offending mail at that point, leaving it on the
servers at HQ for _them_ to deal with the failed bounces. And hopefully
increasing their workload and hence their desire to implement spam checking
themselves :)

--
dwmw2