Re: [exim] Office 365 and Exim sharing a domain

Top Page
Delete this message
Reply to this message
Author: Andy Bennett
Date:  
To: Gary Stainburn
CC: exim-users@exim.org
Subject: Re: [exim] Office 365 and Exim sharing a domain
Hi,

> Appologies for the O.T. post but either my head or my wall will probably give
> in soon.
>
> I've got a traditional email setup with a number of Exim / Dovecot servers
> dotted around my network, all working together and working well.
>
> All users stare the one domain, with lookups using local copies of a
> Postgresql database to route users to their *local* server.
>
> I am now trying to set up an Office 365 pilot which will host a small number
> of trial users. My problem is that I cannot get O365 to share a domain. By
> using the routing abilities of EXIM I can get email into the O365 user's
> mailbox, but I have not been able to get the O365 users to be able to send
> out emails using the ringways.co.uk. It appears that if i want to do that, I
> have to add the while domain to the pilot at which point I cannot route
> emails from the pilot users to the users on the existing set-up.
>
> Does anyone know how I can set up the config so that O365 will allow outgoing
> emails to be from my domain and not the onmicrosoft.com domain?


We had a lot of trouble with this over at ...@knodium.com a couple of
years ago. We found that we couldn't use the O365 MXes and our own
because the O365 ones use BATV and we didn't know the secret so if our
machine sends a message and it bounces to one of the O365 MXes then it
just disappears into a blackhole.

In the end we use our own Exim machines for MX and then forward to the
correct backend on a local_part basis. We've told the O365 config about
our MX machines and it trusts them and doesn't penalise (in their spam
system) anything they send. You can check this exemption is working by
inspecting the headers of messages that end up in an O365 mailbox.


Users using O365 use the O365 relays for outgoing mail and these relays
are smart enough to forward any mail ...@knodium.com that back to our
Exim machine so internal mail works as it should. We're happy to let
those machines relay directly to The Internet so we've not forced the
settings which make it route through our designated relays but it is
possible to do so.

There are actually tutorials on the MS website about how to do all of
this but they don't use standard Internet Mail terminology so they're
rather hard to understand. They also talk about specific use cases so
you have to work out how to translate those into your actual requirements.

If you need any more tips on how we've got things configured then I'll
be happy to share more details.





Also, be sure to get your domain configured on the correct account:
Microsoft can't or won't migrate "inside" their cloud: you can only
migrate a domain "in" or "out". So if you want to move the domain to
another O365 "tenant" you have to copy all of the mailboxes out of the
old account and into the new account. We spent several months doing
support-call ping-pong and didn't get anywhere on that one. :-(



Good luck!





Regards,
@ndy

--
andyjpb@???
http://www.ashurst.eu.org/
0x7EBA75FF