This stops any unwanted telephone calls from being placed!
TIP
If you use networking over a modem, there is a configuration file for pppd
called ppp0, which is located in /etc/ppp/peers. Any commands in
this file automatically run each time the PPP daemon is started. You can
add the line sendmail -q to this file to have your mail queue
automatically processed each time you dial up your Internet connection.Mail Relaying
By default, Postfix does not relay mail that did not originate from the local
domain. This means that if a Postfix installation running at
gracehopper.net receives mail intended for seymourcray.net, and
that mail did not originate from gracehopper.net, the mail is be rejected
and is not relayed. If you want to allow selected domains to relay through
you, add an entry for the domain to the main.cf file like this:
Click here to view code image
mynetworks = 192.168.2.0/24, 10.0.0.2/24, 127.0.0.0/8
The IP address needs to be specified in classless interdomain routing (CIDR)
format. For a handy calculator, head on over to www.subnet-
calculator.com/cidr.php. You must restart Postfix for this change to take
effect.
CAUTION
You need a good reason to relay mail; if you don’t have one, do not do it.
Allowing all domains to relay through you will make you a magnet for
spammers who will use your mail server to send spam. This can lead to
your site being blacklisted by many other sites, which then will not accept
any mail from you or your site’s users—even if the mail is legitimate!Forwarding Email with Aliases
Aliases allow you to have an infinite number of valid recipient addresses on
your system, and you don’t have to worry about creating accounts or other
support files for each address. For example, most systems have
postmaster defined as a valid recipient but do not have an actual login
account named postmaster.
Aliases are configured in the file /etc/aliases. Here is an example of an