I'm hosting the web site of www.domain.com, but my site is not the true SOA for domain.com, nor is it the mx. However, my server IS an MTA for several other sites, some of which need to send mail to users at domain.com. When a mail user on my box tries to send mail to a valid firstname.lastname@example.org address, postfix throws the error: Code: Recipient address rejected: User unknown in local recipient table. I assume this is because, when you setup a site in ISPConfig, as well as users, it automatically adds lines to postfix's virtusertable. So postfix sees that there are domain.com addresses at the site, but not the one being addressed in this message, so it rejects the message. How do I get postfix to honor the MX of the domain before it cares about what is in virtusertable?