Ok i've just set up a webserver. Apache, MySQL, Bind, virtual domains/hosts all work fine and websites can be read from the web.

I've set up virtual e-mail addresses/domains with postfix and vm-pop3d. Sending mail from one of these virtual domains/addresses works fine from anywhere in the world from what I can tell. (Tested using a few proxies). But if I go to send an E-mail from anywhere (I used Hotmail) to one of these addresses then it doesn't work. I just get a delivery failed notification from Hotmail with no returned error logs in the failure notice.

Any suggestions?