Open-xchange forward email for unknown user


I’m doing testing, and slowly migrating specific users to open-xchange. So, I have 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/

mydestination = relayhost = mynetworks = [::ffff:]/104 [::1]/128

I get a 550 5.1.1 Recipient address rejected: User unknown in virtual mailbox table

The easiest setup would be to forward all unknown users in my local to another server.



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 file in ‘transport_maps’ and ‘virtual_transport’.