I am re-designing our company mail services, and we are migrating some mail-boxes to Google for Work. The objective is to have some users in the cloud, and some users on an on-premise Postfix server.
I have currently configured DNS with GMail MX records and configured GMail to forward all mail for unknown users to my Postfix server.
Whenever I send an e-mail from GMail (personal or business), the e-mail gets properly delivered to a correct Postfix mailbox. However, if I try to send e-mail from Postfix to GMail for Work user , I get an error message from Postfix.
Reporting-MTA: dns; glczwe-sp230001.ext.*filtered* X-Postfix-Queue-ID: AFB0A86F24 X-Postfix-Sender: rfc822; petr.balla@*filtered* Arrival-Date: Tue, 9 Feb 2016 20:43:48 +0100 (CET) Final-Recipient: rfc822; dl-cz-accounting@*filtered* Original-Recipient: rfc822;dl-cz-accounting@*filtered* Action: failed Status: 5.1.1 Diagnostic-Code: x-unix; user unknown
Obviously, Postfix handles the domain, so it rejects the e-mail, because the account does not exist locally. I know I could list all the users in /etc/postfix/transport, however I am trying to think of a way that would be easier from a mailbox provisioning perspective. Having to touch both mail-servers, GMail and Postfix when creating new users on a GMail servers is a bit of a pain for my taste.
Does anybody have an idea about a solution for my problem? I believe ith might be very common scenario for all Google for Work users.