RE: [Exim] Exim and Exchange

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Author: Paul Walsh
Date:  
To: Paul Lyons
CC: exim-users
Subject: RE: [Exim] Exim and Exchange

Does your server have a publically routable IP address (eg, a real one,
as opposed to an RFC1618 address like 192.168.something..) (Or, if it


Our setup is such that all passes through a couple of Suns running Exim
3.32. (let's call them sysb and sysb) on it's way to Exchange (ex1, ex2,
ex3) The MX records look something like this:

sysa    IN    A    10.1.1.1
sysb    IN    A    10.1.1.2


ex1    IN    A    10.2.1.1
ex2    IN    A    10.2.1.2
ex3    IN    A    10.2.1.3


exchange    IN    MX    10    ex1.my.dom.ain.
        IN    MX    20    ex2.my.dom.ain.
        IN    MX    30    ex3.my.dom.ain.


@    IN    MX    10    sysA.my.dom.ain.
    IN    MX    20    sysB.my.dom.ain.


So delivery of mail for our domain will be attempted via sysa or, if it's
down, sysb. Exim aliases some.name@??? to ID@??? and
uses the following router to send mail to Exchange:

Exchange_route:
driver = domainlist
ignore_target_hosts = 127.0.0.1
transport = Exchange
route_list = "exchange.my.dom.ain exchange.my.dom.ain bydns"

Exchange Internet Mail Connector (or whatever it's called as I have as
little to do with it as possible)is configured to send outbound mail to
10.1.1.1 (sysa) for onwards delivery. Unfortunately it doesn't look as
though it's possible to configure Exchange to try the IP address of sysb if
sysa is down, so it's necessary to manually reconfigure Exchange to send to
10.1.1.2

The exchange servers are set up to accept mail for the exchange.my.dom.ain
domain. To draw a parallel with your situation, our Suns would be the
equivalent to your ISP's exim systems and ex1 etc., would be equivalent to
your Exchange server.


Are you wanting to accept mail direct to your Exchange server and not via
your ISP, or do you want your ISP to route through Exim to your exchange
server? If the former then something like this in the DNS should work:

; The IP address of your Exchange server on ADSL
ex1.your.dom.ain    IN    A    192.168.128.1


; Route mail for your.dom.ain to your exchange server
your.dom.ain    IN    MX    10 ex1.your.dom.ain.


Then set up exchange to handle mail for your.dom.ain.

If, however, you want your ISP to do the routing, the MX record(s) for
your.dom.ain. would point to their Exim box(es) which would have a router
set up to deliver to ex1.your.dom.ain. Your Exchange box would then need
to be configured to send outbound mail to one of your ISP's Exim boxes.

Hope that helps

Paul Walsh

Senior Systems Administrator, IT Services,
University of Central England, BIRMINGHAM B42 2SU, UK
Tel: +44 (0)121 331 5708    Fax: +44 (0)121 356 2875