I have some internal GNU/Linux servers running in my local network and I want
postfix to send out e-mails to one of my mail accounts on my public server from
where I can check internal e-mails anywhere and anytime.
The solution is to set up postfix with a so-called
satellite system (smarthost) configuration.
There are a lot of good articles with explanations on the Internet, but I just
need the command line magic ;)