The configuration files for Postfix were installed in /etc/postfix. The /etc/postfix directory should now contain a very basic set of configuration files. Here's what it looks like immediately after install:
[root@ntbox postfix]# ls install.cf main.cf master.cf postfix-script
The primary configuration file for Postfix (the working equivalent to /etc/sendmail.cf) is main.cf. The install.cf file contains the initial settings for Postfix which were set up during the RPM installation. The file master.cf is Postfix' master process configuration file. Each line in the master file describes how a mailer component program should be run. In the debugging section we will talk some more about this file. The postfix-script is a wrapper used by Postfix to execute Postfix commands safely for the Linux environment. Let's take a closer look at the install.cf file as this file contains some data which we will need when we start to configure Postfix with main.cf.
The install.cf file is really just a list of the default settings used by the installation program built into the RPM. Here is the text of install.cf taken from our test machine:
# This file was generated by INSTALL.sh config_directory=/etc/postfix daemon_directory=/usr/libexec/postfix command_directory=/usr/sbin queue_directory=/var/spool/postfix sendmail_path=/usr/sbin/sendmail newaliases_path=/usr/bin/newaliases mailq_path=/usr/bin/mailq mail_owner=postfix setgid=no manpages=/usr/man
Much of this is important to know when we start looking at /etc/postfix/main.cf.