Configure your development server to deliver all mail locally

Back in September 2008, I wrote an article on how to configure your virtual machine to deliver email locally (using postfix, cyrus, imap, and sasl). I’ve had to revisit this article recently to test some bulk emailing functionality. I wanted to change my email server configuration to deliver all email locally to ensure clients and coworkers do not receive test emails. After reading a bunch of web articles, I decided to use Postfix’s transport functionality (located /etc/postfix/transport). This configuration file allows you to map email addresses and hostnames to message delivery transports.

I edited this file (/etc/postfix/transport) and added the following to the end of the file:

* discard:

I then edited my postfix configuration file (/etc/postfix/main.cf) and added the following:

transport_maps = hash:/etc/postfix/transport
always_bcc = eric

Reload the transport and restart postfix using the following commands:

postmap /etc/postfix/transport
/etc/init.d/postfix restart

The first configuration change discards all outgoing email, and the second automatically BCC’s my user. Although this is a drastic configuration change, it does exactly what I want: it ensures that email will never be delivered to real world addresses, and any email sent from my development server will end up in my local inbox.

You may have to tweak these settings to find a configuration that works with your development situation. For instance, if you wanted to continue delivery to a certain domain, you could add the following transport:

your.domain :

Update: 2009-06-25

I recently had to create a new virtual machine and I encountered a gotcha. Once I added the line to discard all email I could not receive anything, even if it was set to always BCC me. My hostname for my virtual machine is “VirtualBox-Centos”, so I changed my configuration to the following and delivery resumed:

VirtualBox-Centos.localdomain :
* discard: