I want to make Postfix unable to receive mail. I just want to be able to send mail with Postfix, not the other way around. Is that possible? If so, can anyone tell me how to do that? Thanks.
Inside your (/etc/postfix/)main.cf:
This way it only listen to localhost (via loopback). Make sure you restart (or reload) the server after change.
Choose satellite system.
Provide your ISP's smtp server as the smarthost.
Preferrably choose a valid domain name to mask local adresses.
When asked about which subnets to listen on, provide only the loopback interface's 127.0.0.1
Similarly, only provide localhost (and optionally the hostsname) as final mail destination.
The system will now support a minimum of local mail delivery, accept no mail from external hosts and send all outgoing mail through the smarthost.
Coolwater and Roy are correct, by default 'Satellite' will still internally deliver full addresses for your own hostname. This is wrong for anyone with third party or external MX records. Many options available in reconfigure are not available during install.
So if you want mail to 'fred' to be delivered locally but not
and (to strictly address the question) only send fully qualified mail. The system may still send local mail (cron output etc.) but handling these (aliases, redirection, masquerading,