I've installed Postfix on Ubuntu Server. I'm just using Postfix as an SMTP relay for misc internal items that need SMTP (like scan to email, system alerts, etc). Our email is hosted by Google Apps for business. I seem to have smtp working as a relay for all external domains, but email going to our own addresses on our domain (ie ourcompany.org ) do not get delivered. I believe postfix is trying to deliver it locally. When I look into postfix log I see that an error NOQUEUE: reject: RCPT from [server] and 550 18.104.22.168 and Recipient address rejected: User unknown in local recipient table What configuration do I need to make in postfix so that it treats internal mail address (ourcompany.org) the same as all other mail? Or maybe I'm not approaching it from the wrong angle. All help appreciated.