I’m doing testing, and slowly migrating specific users to open-xchange. So, I have tim@domain.com is still on my old email server.
If bob sends and email to tim, I’d like open-xchange forward the email to the old server. Basically, and unknown user should be forwarded. I was able to do this with Kolab, and I believe I only added/changed the following lines in /etc/postfix/main.cf
This is not possible to configure generally, because the mail server (Postfix) is responsible for an entire domain - so it knows all users of the domain. If a mail should be send to unknown@dom.ain, it will know that the user does not exist.
I was able to do it with Kolab/Postfix with a few simple lines (see original message).
The only way I’ve been able to do it with Open-Xchange is to add every user into UCS and add them into a transport file. If the user is in the transport file, all their email gets forwarded to the other server. If they are not in the transport file, they are local. A bit more of a pain, but better in the long run.
Since I created my own transport file (transport_old_server) I also had to add the transport file to the main.cf file in ‘transport_maps’ and ‘virtual_transport’.