# How to configure postfix to not relay to local virtual domain?

I have set up a SMTP server with iRedMail on Ubuntu 14.04 LTS and everything is working smoothly. I can create new users and send e-mails.

My situation however is a bit more complicated: I need this server to send e-mails on behalf of my domain name "sampledomain.xxx" but I'm using a hosted mail service to receive e-mails. My domain DNS's MX records are set to a different IP than the SMTP server I've just set up. Basically this should be an outgoing-only SMTP server.

The problem arises when I need to use the SMTP server as user1@sampledomain.xxx to user2@sampledomain.xxx because Postfix thinks that mail should be relayed internally, but it doesn't find the address in the virtual domain's mailboxes and thus fail to send the e-mail.

How can I configure Postfix to not relay internally such e-mails and instead resolve MX records and send them as classic e-mails?

Many thanks!

Open your postfix configuration file (usually /etc/postfix/main.cf) in a text editor. I like vim.
$sudo vim /etc/postfix/main.cf  Find the line where mydestination is set. It probably looks something like this: mydestination =$myhostname, localhost.$mydomain, localhost  Comment that line out by prefixing it with a #. # mydestination =$myhostname, localhost.$mydomain, localhost  Add the following line and then save the file. mydestination =  Restart postfix $ service postfix stop
$service postfix start  Postfix will no longer try to deliver 'local' email to this server but will use the SMTP server given by the DNS MX record. • Not sure why this isn't an accepted answer, less still why it was downvoted - worked for me, except I just had to remove just one domain from the list rather than the whole list. – Chris May 17 '17 at 10:07 • Thanks, Chris, I'm glad it worked for you. I've never understood down votes without explanation. Some people just don't seem to get it. – Peter Evans May 23 '17 at 14:54 • That worked for me. It should definitely be considered as right answer. – Adonist Aug 3 '17 at 15:41 • +1 from me ;-) Only needed to remove the$myhostname from the string, but I suppose technically commenting the whole line should be fine as there are no local mailboxes. – Ray Oei Jan 4 '18 at 21:27