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--- ubuntu:email:install_postfix_mail_server_with_dovecot [2020/12/06 12:19] – [Basic Configuration] peter
+++ ubuntu:email:install_postfix_mail_server_with_dovecot [2020/12/06 13:07] (current) – removed peter
@@ Line 1: / Line 1: @@
-====== Ubuntu - Email - Install Postfix Mail Server with Dovecot ======
-**Postfix** is responsible for interacting with the other email servers in the world.
-Postfix is used to either send mail to, or receive mail from, other servers.
-**Dovecot** interacts with your email client (Thunderbird, etc.), and is the intermediary between your email client and Postfix.
-----
-====== Install Postfix ======
-<code bash>
-sudo apt install postfix
-</code>
-----
-===== Virtual Mailboxes =====
-Create a user that will actually own all the virtual mailboxes.
-<code bash>
-useradd -m -r -s /sbin/nologin vmail
-</code>
-<WRAP info>
-**NOTE:**  This creates the user and gives it a home directory: **~vmail**.
-The virtual mailboxes will be placed in this directory.
-Virtual mailboxes allow us to unlink the users of the email system from the users on the underlying operating system.  This means that there can be mailboxes associated with users that do not have Linux accounts, and those users that do have Linux accounts can have multiple email accounts.
-</WRAP>
-----
-===== Configuring Postfix =====
-The configuration files for Postfix are usually found in **/etc/postfix**.
-The two most important files are **main.cf** and **master.cf**.
-----
-==== Basic Configuration ====
-The file **main.cf** will be completely replaced.
-It should start with the basic configuration:
-<file bash /etc/postfix/main.cf>
-mydomain = sharewiz.net
-myhostname = mail2.$mydomain
-myorigin = $mydomain
-mydestination = $myhostname, localhost, localhost.$mydomain, localhost.localdomain
-mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
-inet_interfaces = all
-mailbox_size_limit = 0
-home_mailbox = mail/
-# Prevent bad guys from querying for valid email addresses.
-disable_vrfy_command = yes
-</file>
-<WRAP info>
-**NOTE:**
-  * **myorigin** defines the domain used for outgoing messages.
-  * **mydestination** gives the non-virtual domains for which mail will be accepted.  mydestination should not contain any of your virtual mail domains.
-    * $mydomain is not contained in mydestination. That is intentional.  It will instead be placed in the list of virtual mail domains (described later).
-Postfix will reject any mail that it receives that is not destined for a domain or machine that is not listed in mydestination (or in the virtual mail domains defined later) unless it comes from a machine on the local network.  In this way, mail from the local network can be sent to anyone out onto the open internet and mail from anyone on the open internet can be delivered to a known user, but Postfix will not act as an open relay.
-  * **mynetworks** defines the local network.  In this case the local network is confined to the server itself.
-  * **mailbox_size_limit = 0** is used to disable limits on the size of the mail that can be received into a mailbox.
-  * **home_mailbox** define the name of the mailbox used for local users.  In this case the mail will be placed in a hidden directory in the users home directory and it will take the form of a directory itself (the trailing slash indicates that the maildir format should be used).
-</WRAP>
-----
-==== Local Aliases ====
-<file bash /etc/postfix/main.cf>
-alias_maps = hash:/etc/aliases
-alias_database = hash:/etc/aliases
-# Configure list of users/recipients
-local_recipient_maps = proxy:unix:passwd.byname $alias_maps
-</file>
-<WRAP info>
-**NOTE:**  This requires than an aliases file **/etc/aliases** exists.
-You should not have to create this file nor change it, but if you do change it, you will need to run the following before the changes will take effect:
-<code bash>
-postalias /etc/aliases
-</code>
-</WRAP>
-----
-===== Virtual Mailboxes =====
-How should local delivery be performed?
-Local delivery is that act of moving a piece of email from Postfix to the users mailbox.
-For Local Delivery, we could use:
-  * **Postfix**:  Simpler.
-  * **Dovecot**:  More efficient.  Allows some automated filtering.
-----
-==== Using the Postfix LDA ====
-To configure the Postfix local delivery agent for virtual mailboxes, add the following to main.cf:
-<file bash /etc/postfix/main.cf>
-virtual_mailbox_domains = sharewiz.net abcd.com
-virtual_mailbox_maps = hash:/etc/postfix/virtual_mailbox_maps
-virtual_alias_maps = hash:/etc/postfix/virtual_alias_maps
-virtual_mailbox_base=/home/vmail
-virtual_uid_maps = static:997
-virtual_gid_maps = static:997
-virtual_minimum_uid = 997
-</file>
-<WRAP info>
-**NOTE:** There are two virtual mail domains: sharewiz.net and abcd.com defined.
-These two domains will be added to the list of domains for which Postfix will accept mail.
-The actual virtual mailboxes are defined in **/etc/postfix/virtual_mailbox_maps**.  An example of this file is:
-<file bash /etc/postfix/virtual_mailbox_maps>
-peter@sharewiz.net      sharewiz.net/peter/mail/
-peter@abcd.net      abcd.com/peter/mail/
-admin@sharewiz.net       sharewiz.net/admin/mail/
-</file>
-Each line defines a virtual mailbox and consists of two items.
-  * The first item is the email address of the virtual mailbox (should be lowercase).
-  * The second item is the physical address on disk.
-    * **NOTE:** Each of the second entries ends with a slash.  This indicates that the maildir format should be used rather than the mbox format (maildir places the mail into individual files inside the maildir whereas mbox is one giant file that contains the all of the mail messages).
-    * The physical address of the mailbox specified must be consistent with what Dovecot expects, which is set in the userdb section of the Dovecot configuration file. The correspondence is a bit complicated.
-The mail directory for **peter@sharewiz.net** would be **/home/vmail/sharewiz.net/peter/mail/**.
-Whenever you modify this file you must run **postmap** in order to Postfix to be aware of the changes:
-<code bash>
-postmap /etc/postfix/virtual_mailbox_maps
-</code>
-</WRAP>