I've been trying for some days now, but till now with no luck. In ISPconfig I've got a domain www.somename.com (lets call this server server_1). The website and DNS is running on this ISPconfig server (server_1), but the email for that domain is on an other server (lets call it server_2) Within ISPconfig (server 1) I've created the domain www.somename.com. For the domain www.somename.com I've enabled Create DNS. I've also created an user & email as I needed it to FTP to the site. I also set the Mailserver (under the tab options) to External Mailserver. In the DNS for domainname.com I've setthe MX record to an A record that points to the server that is used for mail. Problem. When I email with a user account that does run on the ISPconfig (server_1) to somename.com, the mail will not go to server_2 (it get an error saying "Your message did not reach some or all of the intended recipients. Recipient address rejected: User unknown in local recipient table" (note that this is only when I use an email account that is on server_1) Looking at /etc/postfix/local-host-names it does still show somename.com Should the option "External Mailserver" not remove this from the local-host-names file? When I use an account that is NOT running op server_1, mail (gmail, hotmail etc... ) all is working fine for somename.com Anyone here who might know what is going on?