Exchange 2010 forward outgoing domain emails to a internal IP

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http://serverfault.com – I want forward to a internal email server, all outgoing email to test.com domain... Internal email server is a linux server... I have exchange and linux email server(postfix) with different domains, I need forward the emails from my exchange server to the linux server internal IP, the target domain is a .com domain. How can I do that? is possible? outgoing emails to test.com->send to server (HowTos)