Postfix: how to force MX lookup for 'local' domain?

[random.guy]

Let's say my server's hostname is site.com. I also run various web based software packages, which send out e-mail to customers. This works great. The problem is that my server also sends out e-mail to user@site.com.

The problem is that the site.com e-mail is not hosted on this server, it's actually hosted on a 3rd party e-mail server, so I am not getting these e-mails. Is there a way of forcing Postfix to use the MX records for site.com, even if this is the local name of the server? The server will not be receiving ANY e-mail, just send out.

Thanks!

[jnsc]

There is an "External mailserver" option in ISPConfig. Don't forget to set it also for co-domains.

[random.guy]

Oops, I didn't realize I was in the ISPConfig2 subforum, this is about a clean postfix install on Ubuntu 10.04 LTS. Hopefully a mod can move this thread.

I am hoping I can avoid hardcoding the SMTP server, or I will run into problems when the 3rd party changes its MX records. I just want to force postfix to look up the MX records for site.com whenever e-mail is sent to site.com.

Mods: please move this thread, thanks!

[till]

I just want to force postfix to look up the MX records for site.com whenever e-mail is sent to site.com.

Postfix is always doing this by default. So no need to configure something. Just do not create site.com as local email domain.

[random.guy]

Ok, finally figured it out. It looks like I had to set mydestination to nothing:

mydestination =

[till]

Mydestination has to be set to the hostname of the server, it my not be empty. Just make sure that you use a subdomain for it as it is described in the perfect setup manuals.