The General options section contains a lot of fields, but not all are important. You can choose to send all outgoing mails to a relay server, or to deliver them directly through Send outgoing mail via host. If you want to keep trace of all your e-mails, put an address in Address that receives bcc of each message, and the latter will receive a copy of each mail. For advanced administration, you could change the Postfix database type in the Default database type field from hash to dbm. You can specify the Time in hours before sending a warning for no delivery. If you plan to use this mail server only to receive mails from the Internet, you could specify the public network interface in the Network interfaces for receiving mail field. If you want to change the system user who is running Postfix, change it in Mail owner. The other options are system-specific, and are not important for configuring Postfix.

In the Canonical mapping section, you can specify mapping table files, which are used to rewrite e-mail headers managed by Postfix. For example, in Address mapping lookup tables, you could associate the name of employees with their e-mails: John.Doe@example.com and jdoe@example.com.

In the Virtual domains section, you can specify domain table files, which are used by Postfix to redirect specific e-mails or entire domains to another server.

The Transport mapping section tells Postfix which files contain domains to relay. In this file, specify all e-mails from a domain which is accepted by your mail server, which then has to be resent to another host.

The Relocating mapping section tells Postfix what to do with nonexistent e-mails or domains.

The Local delivery section contains options to help you configure the “life” of e-mails after Postfix receives them. It looks for a .forward file in user's home directories (which indicate the e-mail address to send the mail back to); with Search list for forward, give the e-mail to procmail for filtering (External command to use instead of mailbox delivery), and then delivered to the Spool directory.

In the SMTP server options section, you can prevent receiving spam mail by configuring the DNS domains for blacklist lookups field. Some Internet servers run public DNSs with blacklisted hosts. These mail hosts are relaying spam mail. So configuring this option allows Postfix to look in these databases before accepting mails. All Postfix response in the bottom of the page should be kept to the default value.

The Debugging features section contains two options. The first one, List of domain/network patterns for which verbose log is enabled, specifies a list of hosts and domains, for which Postfix logs have to be verbose. The second one configures the log's verbosity level.

If LDAP is installed on your system, you could access and configure options in the LDAP lookups section.