Changing the destination domain name - for service changes

[kmel...@dotheyknow.net]

I have a quick question, which may or may not have a quick answer.

I have a customer who currently use Google Apps on two completely separate instances. For licensing issues, and to simplify administration moving forward, they would like to combine the instances. In order for this to be completed, there would normally be some down-time while the OLD instance is removed, and available for set up in the NEW location. To avoid this down-time, I would like to know if the following is possible with Postfix.

ABC.COM - Fully set up
XYZ.COM - Fully set up (Needs to be purged and moved underneath ABC.COM)

If I switch MX records to a Postfix server, is it possible for the server to strip the @XYZ.COM from every <username>@XYZ.COM email and replace it with <username>@ABC.COM?

This would help avoid any downtime for purging the domain, as mail could still flow to the email address, and make it to a user on the ABC.COM side.

[d.agosti...@gmail.com]

Hi

Postfix can only happend domains if the domain part is missing. So there is not such think in postfix but it is very easy to do this with an external filter application.

In practice you can do that by using a postfix filter which will call an external application (a bash script or a binary one).
http://www.postfix.org/FILTER_README.html

The bash script will only replace XYZ.COM by ABC.COM and reinject emails in postfix (or an other smtp server).

Regards

Victor d'Agostino