Re: [Exim] Behaviour I would not expect on callout

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Author: Philip Hazel
Date:  
To: Xander D Harkness
CC: 'Exim-User'
Subject: Re: [Exim] Behaviour I would not expect on callout
On Thu, 4 Jul 2002, Xander D Harkness wrote:

> I have a rewrite rule in a host that sends mail to me.
>
> The rewrite rule is:
>
> root@???     root-wks@???

>
> The server it is trying to relay through does a callout to the adsl line
> that wks.harkness.co.uk is connecting from (where all incoming ports are
> firewalled), rather than trying to do a callout to the mx record that
> would serve harkness.co.uk. It obviously fails and rejects the mail.


The ACL is run before the address is rewritten by normal rewriting
rules. Consequently, it is verifying root@???, not
root-wks@???. I presume that wks.harkness.co.uk routes to
that ADSL line.

> Am I missing something or is it designed like this. How would I enable
> an mx look up rather than sending host?


You have a choice!

1. Use SMTP-time rewriting. That gets done as soon as the SMTP command
is received, before the ACL is run. Add an S flag to your rule. If you
want the same rule for headers, etc, add other flags as well, because S
on its own suppresses the other flags.

2. Set up a router, with verify_only if necessary, that routes
wks.harkness.co.uk appropriately.


Hmm. Looking at the DNS, I find

wks.harkness.co.uk.         MX 10 relay1.harkness.co.uk.


so maybe my assumptions above are wrong. What is supposed to happen is
that the callout is done to the same host, and using the same interface,
that a message sent to that address would use. What output do you get
for

exim -bvs root@???

? That should tell you how it routed it. (Add -d for debugging info.)

--
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.