setting up a mailserver on my spare ubuntu box

set up my postfix and mysql mailserver using the following link http://flurdy.com/docs/postfix/

needed to modify the setup of postfix to authenticate against my ISPs smtp server .. byd doing this ...

Added the following settings to /etc/postfix/main.cf:
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options =

Create /etc/postfix/sasl_passwd as follows:
my.mail.relay.net username:password

Because the password is in cleartext make it root only:
# chown root:root /etc/postfix/sasl_passwd && chmod 600 /etc/postfix/sasl_passwd

Create the hash file:
# postmap /etc/postfix/sasl_passwd

Make the hash file world readable:
# chmod 644 /etc/postfix/sasl_passwd

Reload the Postfix config:
# /etc/init.d/postfix reload