Starting Postfix the First Time
There are two important issues to deal with before
starting Postfix for the first time. The first is how your system
identifies itself. Postfix uses a configuration parameter called
myhostname , which must be set to the fully qualified hostname of the
system Postfix is running on. Once Postfix knows the fully qualified
hostname, it can use that hostname to set default values for other
important parameters, such as mydomain. If the parameter myhostname is not set, Postfix defaults to the
hostname reported by the system itself. There is a complete discussion
of myhostname later in the chapter.
You can see what name your system reports with the Unix hostname
command:
$ hostname
mail.example.comA fully qualified hostname is comprised of both the individual hostname and the domain in which it resides. Some systems are configured with their simple hostname, rather than its fully qualified version:
$ hostname
mailIf your system is configured with just its simple hostname,
Postfix cannot determine what the fully qualified name is. You must
therefore explicitly set the myhostname parameter. You can do this quite
easily with the postconf Postfix command. The postconf command is a Postfix utility that
provides an easy way to get a variety of information about your Postfix
system. One of its functions is to display or change a specific
configuration parameter. You can use it to set the myhostname parameter:
# postconf -e myhostname=mail.example.comThe -e