Bounce processing Docker-version

This article:

explains how to setup Bounce processing. But this article refers to an old (non-Docker) version of Oempro. Does the content of this article still apply for the newest version?
FYI: We installed Oempro and Postfix on the same server and would like to know how to use Email Piping with Postfix on the server and Oempro in an container.

Thanks a lot for any help,


Hi José, that article refers to old Oempro versions (non-Docker) versions.

Current Oempro version comes with a built-in SMTP server for inbound SMTP connections (bounce, FBL and reply processing/forwarding). It comes and runs out of the box on port 25 and 587. Therefore, if you have postfix running on your host server and if it allocates port 25 and/or 587, this will cause a conflict.

If you are using Oempro v4.14.3 or higher, please remove or disable postfix on the host machine, set your MX records of sender domains to the IP address of your Oempro server.

Hope this helps.


Dear Cem,

thanks for your reply. Because of the port conflict we used a different port for Postfix: 2525. So, Postfix is not interfering with Oempro. And MX record of is set to the server where Oempro is installed (inside a container) and the port mapping has been configured.
Is it possible to run Oempro (v4.14.3) in a container on a server where Postfix (listening on port 2525) is installed? If so, what has to be done that Oempro processes bounces correctly? Right now, our Oempro installation does not process the bounces, i.e. bounced emails show up as Not Bounced and are not unsubscribed from the list.

Example from the logfile:

Sep 20 12:14:36 static1 postfix/smtp[25065]: 488B3102D31: to=<[>](, [[]:25]([]:25/), delay=2.8, delays=0.09/0/0.63/2.1, dsn=5.0.0, status=bounced (host [[]]([]/) said: 550 User not found: []( (in reply to RCPT TO command))
Sep 20 12:19:15 static1 postfix/smtp[9618]: 7FE15103E64: to=<[>](, [[]:25]([]:25/), delay=0.27, delays=0.1/0/0.05/0.12, dsn=5.0.0, status=bounced (host [[]]([]/) said: 550 Message was not accepted -- invalid mailbox.  Local mailbox []( is unavailable: user not found (in reply to end of DATA command))
Sep 20 12:19:25 static1 postfix/smtp[9936]: 1829F103EC8: to=<>, [[]:25]([]:25/), delay=0.28, delays=0.06/0/0.1/0.12, dsn=5.0.0, status=bounced (host [[]]([]/) said: 550 Message was not accepted -- invalid mailbox.  Local mailbox is unavailable: user not found (in reply to end of DATA command))

These three emails are hard-bounced but at Oempro are still subscribed and “Not Bounced”:

Attached two screenshots showing our configuration.

Here is the header of the newsletter we sent out, and where bounces where not detected:

Is there a documentation (similar to the article for the old Oempro version) which we can refer to in order to see what we have to do so that bounces are processed?

Thanks a lot for any information you can give us.

Kind regards,


Hi José, Oempro already runs inside a few Docker containers;

oempro_app => Front-end and micro-services
oempro_system => Background processes and new micro-services
oempro_bounce => The built-in SMTP server for bounce/fbl/reply processing
oempro_mailhog => The Mailhog test environment for emails
oempro_haproxy => The HAProxy load balancer

Can you please confirm you are running all these Docker containers?


By the way, with the release of Oempro v4.14.4 in a few weeks, there will be two more Docker containers:

oempro_rabbitmq => queuing container
oempro_redis => caching container

Cem Hurturk

I can confirm that these containers are running:

Hey José, thanks for the reply.

You can run postfix on a different port, on the same server with Oempro docker containers. As long as there’s no port conflict, there will be no problem.

I think it will be better if we can take a quick look what has been set on your Oempro admin area. Can you please reach us via and provide us your admin login credentials? Let’s check your delivery servers, sender domains and connectivity.

Cem Hurturk