First off, I'm a n00b when it comes to Linux, so please bear with me!
I have a Debian 5 (Lenny) system set up and working, so no problems there at the moment.
I own numerous domain names, and want to be able to capture the email that is sent to them and forward it to an external email address. Initially, I don't really care what email address the mail is sent to as long as the MX record is pointing to my server, I just want it to accept it and fire it our to an external email address. It shouldn't store the mail or anything, simply relay it. It might be nice in the future to set up some rules for different addresses to go to different email addresses, but I'm not really concerned with that at the moment.
Sorry if this is a stupidly simple thing that I should be able to do without help, but Mr Google isn't helping me with this one.
Thanks in advance.