Re: [exim] Newbie question - Setup on a MS Exchange network

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Author: Tim Jackson
Date:  
To: exim-users
Subject: Re: [exim] Newbie question - Setup on a MS Exchange network
James Mitchell wrote:

> I have been fighting with sendmail, postfix and exim over the last couple of weeks to
> get my new system sorted. I'm a bit of a Linux newbie never mind
> administering mail in any respect!


OK cool, well bear in mind that if you're serious about administering
mail then there's quite a bit to learn especially in the unfriendly
world we have of spam and viruses, including spammers who know a lot
about this stuff. So you have to be ready to read some background,
understand what you're doing and look at things from the point of view
of someone receiving your mail. (Maybe not so important if you're just
working on a local network, but still - it's good to get things right
and it's less likely to cause weird problems). Some basic things to
understand:

- SMTP. It's good to be able to conduct a basic SMTP transaction
yourself, using "telnet".

- Envelope sender. Not to be confused with the "header sender".

- DNS. Understand both forwards (hostname to IP) and reverse (IP to
hostname) DNS, and how this appears both from the point of view of an
internal network and to the "outside world".

- Exim :) It's very powerful and flexible, and actually very easy to get
to do what you want when you get over the initial learning curve. Make
sure you're using Exim 4 (preferably a recent version). Buying a copy
of the Exim 4 book (www.uit.co.uk/exim-book/) would be a great way to
get yourself up to speed. Understand the basics of routers (for deciding
how a message is handled), ACLs (for access control) and transports (for
delivering messages to somewhere else). Don't be afraid to use "exim
-bt" (test how an address is routed), "exim -bh" (test an SMTP session)
and the "-v" option.

- HELO/EHLO - this is what your machine identifies itself to others as

> My Fedora Core 5 PC is hosting a wiki, bugzilla and RT request tracker.
> It is on a local network. Internal mail goes through a gateway and
> exchange server, external mail also comes through an MX server which
> is off site.

[...]
> I want to be able to send to and receive from anybody@???


OK, first of all, unless your name is Hansoo Bae and you live in Seoul,
you don't own "mycompany.net" so let's either use the dedicated example
domains example.com/example.net, or use your real details (the latter
lets people help you more easily rather than battling layers of
obfuscation). Let's take your issues separately:

a) sending to [user]@traveleads.net. Well, this should be pretty
straightforward but it depends how your internal DNS is set up. Ideally,
when you do "host -tmx traveleads.net" from an internal machine it
should point towards the *internal* mailserver that handles your mail
(this is called split-horizon DNS) but most likely that is not the case.
There are a number of strategies for handling this but the simplest is
probably to use what's called a "manualroute" router which overrides DNS
and forces mail for a certain domain to go to a particular server. For
example, find out the *internal* name of your mailserver (e.g.
mail.mycompany.local) and put a router like this at the top of your
router list (remember, routers are handled in order):

route_company_mail:
    driver = manualroute
    domains = traveleads.net
    route_data = mail.mycompany.local


b) For incoming mail, well, I don't know what you want really. You say
you already have incoming mail handled first by offsite MXes and then by
an internal server. What more do you want? Do you want mail to be routed
to your Fedora machine for script handling or something?

> What would I need to change in the exim configuration? (After a fresh installation...)


Did you install from Fedora Extras using "yum install exim"?

> Unless expressly stated otherwise, I am a banana etc.

[...continues...]
[...etc...]
[...]

Please keep this stuff off the list. It's condescending and inappropriate.

Tim