[Kroupware] how to send/receive emails?

[Alexander Marx]

Hi List!
I have a big problem.
So far:
I installed the kolab server today on a Knoppix Debian (woody)
After rebuilding all SRC.RPM'S and changing the start-skript as
described in the QIM, i managed to get the Server run.

then i logged in as manager and added the user "testuser".

After that, i startet another computer (LINUX Mandrake9.1) and startet
KMail. In KMail i set up the KOLAb Server as IMAP and SMTP SERVER and
created an Account "testuser.

Then i tried to send myself an email over the kolab server. But the
Server said: "RELAYING DENIED" Why? the user is testuser at localhost.
i have no local SMTP or SENDMAIL on the MANDRAKE.

Then i tried to send an email via telnet. the server accepted, but the
mail never reaches the destination. 

Am i only able to send/receive Email with a KOLAB-CLIENT?