We are using Google Apps for Business for our mail server, but require a global signature (simple HTML) to be appended to every message sent. This is not a feature of Google Apps, although it is possible to use an Outbound mail gateway.
I was wondering if it would be applicable to set up a simple SMTP server to append the signature, or if that would be overkill. If so, could someone write a short guide to the best email server to use and how to do this simple task, as we have never set up our own email server (although have set up plenty of web servers before).
We have a Debian Squeeze server with an external IP address that we would like to use.