apt-get install postfix

or choose dpkg-reconfigure postfix when you allready installed postfix before.

The configuration working for me is “satelite”.

1. System Mail Name: your maildomain name (interblc.com) not the dns name of your server.
2. SMTP relay host:smtp.1und1.de
3. Root and Postmaster mail recipient: your user account or external email address
4. Other destinations to accept mail for: your servername, localhost.localdomain,localhost
5. Force synchronous updates on mail queue: If you have ext3 oder reiser NO otherwise better YES
6. Local Networks: 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
7. Procmail for local delivery: Yes
8. Mailbox size limit: 0
9. Local address extension character: +
10. Internet Protocol:All

Edit /etc/postfix/main.cf and add these lines at the end:

smtp_sasl_auth_enable = yes
smtp_sasl_security_options = noanonymous
smtp_sasl_password_maps = hash:/etc/postfix/sasl_password

Create /etc/postfox/sasl_password with one line:

smtp.1und1.de MAILACCOUNT_at_1und1:PASSWD

Create and db file from this passwd file with

postmap /etc/postfix/sasl_password

Restart postfix with:

/etc/init.d/postfix restart
Now it should work. Give it a try with

date | mail -s “testing” regen@wetter.de

and watch the logfile with

tail -f /var/log/mail.log