Hi, > Where will the mail go if outside senders wants to send mail 10.20.30.41 > or 10.20.30.42 ????. These are private IP addresses and no one outside your network will have access to 10.x.x.x by definition. You need to have public IP's if you want outside IP's to access, or have all the senders be on the same private subnet via VPN. See http://www.faqs.org/rfcs/rfc1918.html and http://support.microsoft.com/kb/q307287/ for the complete list of reserved private IPs. Mike