I have follow this tutorial http://howtoforge.com/virtual-users-and-domains-postfix-courier-mysql-centos5.1 and in my /var/log/maillog say this: postfix/smtpd: fatal SASL per-process initialization failed when Exec telnet localhost 25
You posted this in the ispconfig forum, but this tutorial is not compatible with ISPConfig. If you want to install ISPConfig, use on of the tutorials listed on the ispconfig documentation page.
