I just did a new install of exchange 2003 and I still have exchange 5.5 running on a different domain. I want to play around with 2003 till I'm ready to go live. I understand I'll have to change my mx records to start receiving mail but should I be able to send out mail. If so what did I not setup because it is not sending mail out of the office. I did add the permission for the new server to send email on my firewall.