Felix,

Postfix was primarily designed for a server to deliver email to another server
using the SMTP protocol on both ends (and not SMTP on one end, and POP3 on the
other end).

However, some providers such as Google's Gmail, allow email to be relayed via
their authenticated SMTP service. Here's an article on how to do that:


http://souptonuts.sourceforge.net/postfix_tutorial.html

But be forewarned that the installation of the above is not for the beginner,
but is more like the final exam of Postfix installation.

The easiest thing to do is to find someone that will allow you to relay email
through their site. If you can't find anyone, send me a private email and I
can refer you to someone I know who would probably do it for a nominal fee.
--
Greg



Felix Saphir wrote:
> Hi!
>
> I must say, I'm new to this topic, and browsing this newsgroup I
> couldn't something similar. What I'd like to know, if it is possible to
> configure postfix to send mail
> - to some specific domain(s) (say gmx.net) via my mail account at
> yahoo using a SMTP AUTH
> - to all other domains directly?
>
> The 'problem' is, that gmx (and probably other providers as well)
> categorize my mail as spam, because my computer's domainname doesn't
> match my email-domain ... The idea is, to use some authenticated
> transport in this case. Bad idea?
>
> I'm sorry, if this is a standard question, which has been answered long
> ago in a FAQ. Where can I find it?
>
> TIA,
> Felix Saphir