Re: [Exim] geographically diverse mail servers, all the same…

Hi,

> I have a setup where a mail domain is handled by several M
> Sex Change servers. I now have the opportunity to have ppl
> change the MX of the domain to point to my server so I can
> shortcut all mails to our department while all other emails
> need to be sent to the exchange servers, still.

We have kind of the same setup here at our offices. Here's something to
think about: what is the 'local domain' setting of the Exchange servers? In
other words: what happens when someone using sExChange tries to send mail to
someone in you department? Will that message ever leave the server?

> So, basically, I could come up with two options, please let
> me know I am too blind to see or it should work...
>
> a) Like UUCP, we are MX for the domain, it's not in
> local_domains, we have a router for it that will happily
> forward the rest of it all, but then what?
>
> b) mail domain is in local_domains, we have an alias file
> for it, and then we need to forward the rest of the mail
> domain to some other server.

I'll tell you our solution. First off, let me tell you we use Sendmail, not
Exim, but this should be doable in Exim as well. The MX for the domain
points to the Sendmail host. On it resides a file with local parts that need
to be handled by Exchange. This is because the number of addresses handled
by the Sendmail box is bigger, but it could easily be switched of course.
Matching local parts are routed to the nearest Exchange server. In Exim, you
would use the manualroute driver:

smart_route:
driver = manualroute
route_list = * your.exchange.server
transport = remote_smtp

Of course, you'd have to add a condition to match the local part to the
file, but I can't write that off the top of my head.

Then, to make internal mail to our department actually leaving the Exchange
environment, we created a subdomain 'tech.ourcompany.com' and all members in
our department have a 'contact' in Exchange, with a foreign (SMTP)
e-mailaddress like localpart@???. Mail for this domain is
then handled by the Sendmail box.

Good luck,
Martijn.