Linux System Administration

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Chapter 5: Mail

Some simple and useful customizations you may need to make include the following:

• Typically,

mydestination lists the domains that appear in the email addresses of

local users; that is, the domains for which Postfix accepts and delivers mail. By

default, Postfix accepts mail destined for

$myhostname and localhost.$mydomain,

the host on which Postfix is running. You can specify that the system should

accept mail for your whole domain by adding

$mydomain to the list:

mydestination = $myhostname, localhost.$mydomain, $mydomain

• You can tell Postfix which hosts you want to allow to relay mail by setting the

mynetworks parameter. (If you set mynetworks, Postfix ignores the mynetworks_

style

parameter.) You can provide one or more IP addresses and/or use the net-

work/netmask notation (e.g.,

151.164.28.0/28). This parameter is useful when

you wish to provide relaying to hosts outside your network—for example, to

executives working at home, salesmen on the road, etc.

We will make some other changes to /etc/postfix/main.cf later in this chapter, to add

allow authentication and password encryption.

Testing Mail

With Debian’s configuration in place, you can receive and send email from your shell

account. The following is an example of two test messages sent by one of this book’s

authors. First, I used a Gmail account to send a mail message to a user account on

the server2.centralsoft.org