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= How to set-up Postfix =

 * Audience: Advanced E-Mail set-up
 * Requires: MacPorts >= 1.6, mail/postfix, shells/zsh-devel

== Introduction ==

This How-to is part of the [wiki:howto/SetupFetchmail Fetchmail] ->  [wiki:howto/SetupPostfix Postfix] -> [wiki:howto/SetupDovecot Dovecot] advanced e-Mail set-up.

[wikipedia:Postfix_%28software%29 Postfix] is a [wikipedia:Mail_transfer_agent mail transfer agent] which can distribute your in- and out-bound mail. The set-up described here will distribute inbound mail to a [wikipedia:Dovecot_%28software%29 Dovecot]  [wikipedia:Internet_Message_Access_Protocol IMAP] server and outbound mail to an [wikipedia:Internet_service_provider internet service provider].

Distribution of E-Mail directly to the end receiver is one of the joys of the internet which has been destroyed by [wikipedia:E-mail_spam SPAM]. 

== Installation ==

First set-up a mail storage where postfix will store your mail. See [wiki:howto/SetupDovecot Dovecot] for a possible set-up. Without a proper mail storage you might have difficulty accessing your mail later.

=== Z-Shell ===

Install Z-Shell if you are planning to use the attached command files:

{{{
sudo port install zsh-devel
}}}

=== Postfix ===

We'll want everything, so use the following script to get it:

{{{
#!/opt/local/bin/bash

declare -a toInstall
toInstall=( \
            postfix+dovecot_sasl+tls+pcre+mysql5+postgresql90 postgrey \
            dovecot2+ldap+mysql5+postgresql90 dovecot2-sieve \
            fetchmail \
            squirrelmail \
         )

for doInstall in ${toInstall[@]}
do
    (sudo port install ${doInstall//+/ +}) ; wait
done

exit
}}}

== Configuration ==

The configuration is done several files of which we'll need at least three:
 1. master.cf
 1. main.cf
 1. alias

=== Step 0: '''master.cf''' ===

Don't mess with this file at all at this point in the process !!!

=== Step 1: '''setup main.cf''' ===

You'll find all the default settings in '''/opt/local/etc/postfix/main.cf.default''' - all of these settings are explained in some depth here [http://www.postfix.org/postconf.5.html postconf.5] or {{{man 5 postconf}}}.  You'll find a sample primary configuration in '''/opt/local/etc/postfix/main.cf.sample'''. '''main.cf.sample''' is extensively commented, but to get an overview of the which setting are present in the file execute this command:

{{{
grep ' =' /opt/local/etc/postfix/main.cf.default
}}}

We'll change some of them in the following, but a lot of them has to be left alone and are not to be messed with under most circumstances as you'll completely mess up your configuration if you do so - you have been duly warned !

==== sending email ====

Let's start by getting postfix to send email from the local computer. I'm assuming that you'll be running a webserver that'll need to send and receive eg confirmation email as well as receiving the general email for one or more domains.

The {{{hostname}}} command will give you an a value for what your computer is called, but this is in many cases not a useful name. If you get your IP-number or DNS-settings from a DHCP-server the rDNS-name will be your hostname eg '''4604ds1-ynoe.2.fullrate.dk''' and that's not what you in most cases want your recipients to see as the sending computer. Furthermore, {{{hostname}}} only reflects what the first interface as listed in the Network Preferences Pane is called.

{{{
# The myhostname parameter specifies the internet hostname of this
# mail system. The default is to use the fully-qualified domain name
# from gethostname(). $myhostname is used as a default value for many
# other configuration parameters.
#
#myhostname = host.domain.tld
#myhostname = virtual.domain.tld
myhostname  = computer.example.com

# The mydomain parameter specifies the local internet domain name.
# The default is to use $myhostname minus the first component.
# $mydomain is used as a default value for many other configuration
# parameters.
#
#mydomain = domain.tld
#mydomain = domain.tld
mydomain  = example.com

# The myorigin parameter specifies the domain that locally-posted
# mail appears to come from. The default is to append $myhostname,
#
#myorigin = $myhostname
#myorigin = $mydomain
#myorigin = $myhostname
#myorigin = $mydomain
myorigin  = $mydomain
}}}

Setting '''inet_interfaces''' to '''localhost''' effectively blocks receipt of email. We'll change this setting when we look at receiving email.
{{{
# The inet_interfaces parameter specifies the network interface
# addresses that this mail system receives mail on.  By default,
# the software claims all active interfaces on the machine. The
# parameter also controls delivery of mail to user@[ip.address].
#
#inet_interfaces = all
#inet_interfaces = $myhostname
#inet_interfaces = $myhostname, localhost
inet_interfaces  = localhost
}}}

This blocks other computers from relaying email through your computer
{{{
#mynetworks_style = class
#mynetworks_style = subnet
#mynetworks_style = host
mynetworks_style  = host
}}}

Your outbound mail might need to go through a relayhost as most of us can't send e-mail directly anymore. Due to spam from bot-nets many ISPs block port 25 in their firewall. Mostly it'll be '''smtp.ISP-name.tld''' or something like that, but you ought to be able to find it on the ISPs website. This is also the setting you use in Mail.app for sending email.
{{{
#relayhost = $mydomain
#relayhost = [gateway.my.domain]
#relayhost = [mailserver.isp.tld]
#relayhost = uucphost
#relayhost = [an.ip.add.ress]
relayhost  = [smtp.isp-name.com]
}}}


=== Step 2: '''setup of aliases''' ===

We'll need at least one entry in the aliases database. If aliases.db isn't present, the postfix master will start, but upon the first activity you'll get repeated lines of this kind :
{{{
Jun 17 23:03:52 Pro17 postfix/master[262]: warning: /opt/local/libexec/postfix/smtpd: bad command startup -- throttling
Jun 17 23:04:52 Pro17 postfix/smtpd[17162]: fatal: open database /opt/local/etc/postfix/aliases.db: No such file or directory
Jun 17 23:04:53 Pro17 postfix/master[262]: warning: process /opt/local/libexec/postfix/smtpd pid 17162 exit status 1
}}}

These are lines in main.cf of interest:
{{{
#alias_maps = dbm:/etc/aliases
#alias_maps = hash:/etc/aliases
#alias_maps = hash:/etc/aliases, nis:mail.aliases
#alias_maps = netinfo:/aliases
#alias_database = dbm:/etc/aliases
#alias_database = dbm:/etc/mail/aliases
#alias_database = hash:/etc/aliases
#alias_database = hash:/etc/aliases, hash:/opt/majordomo/aliases
}}}

At present, we'll simply go with the default values
{{{
alias_database = hash:/opt/local/etc/postfix/aliases
alias_maps = hash:/opt/local/etc/postfix/aliases
}}}
and not change anything at all in main.cf

aliases.db is created on the basis of the flat file aliases. Actually, we'll only need to edit one single line in aliases in order to get things working: 

{{{
# Person who should get root's mail. Don't receive mail as root!
#root:		you
}}}

Un-comment the line starting with '''#root''' and change '''you''' to one of the following two options
 1. an ordinary email address: "person@domain.tld"
 1. the short name of a local user
Then, just issue this command : {{{newaliases}}} and aliases.db will be created for you.

=== Step 3: '''starting the daemon''' ===

[attachment:Restart_Postfix.command]  This command creates or updates the database files. Run via "sudo."

=== Step 4: '''testing the deamon''' ===

The attached [attachment:Test_Postfix.command] will send a test e-mail to your self - provided you replaced {{{my_name}}} and {{{my_computer}}} with your own name and computer name.

== Optional Parts ==

=== '''TODO: What else can be done?''' ===

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