postfix-users October 2010 archive
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postfix-users: Re: Deliver to non-local users from domain.

Re: Deliver to non-local users from domain.

From: Nikolai K. Bochev <n.bochev_at_nospam>
Date: Sat Oct 09 2010 - 21:43:37 GMT
To: Michael Saldivar <>

Yes i already have that kind of setup up and running.
The problem that i am describing is when the exchange and the postfix server both have the same domain, i.e. The mx record will point to the exchange and they will forward all mail that doesn't match a local recipient to us. What i want to achieve is the same - i.e. not to have to create each mail user + transport mapping for him.
I know zimbra does this ( ), but as far as i can see they define transport for the domain + transport for each user + a catch-all that does ->

On Fri, Oct 8, 2010 at 5:06 AM, Nikolai K. Bochev < > wrote:

Hello list,

I have one domain , with several users in it. Most of them , will be migrated to a exchange server, which will later be the mx record for that domain. The exchange server will redirect emails for users not in his database to the postfix/cyrus server i run.

The problem is, when someone tries to send an email from postfix/cyrus user to a user on the same domain that is hosted on the exchange. I know i can create local boxes, and setup up transport maps for each of those boxes. What i am wondering is - is there any way that i can tell postfix to relay mail for a domain he owns if no local user exists ?

We have a similar set-up. If you have an internal domain (Active Directory) that is different than your external domain, in the virtual file on your Postfix machine, on the left column put the user's external email address, and on the right put what Exchange recognizes as their FQDN internal address. For example: user@exchange.example.local

This assumes Exchange is part of the Active Directory domain example.local, and you have an MX and A record for it on your internal DNS server.

-- Nikolai K. Bochev System Administrator