= Dovecot =

'''`dovecot(1)`''' is an [[Email/IMAP|IMAP]] and [[Email/POP|POP3]] [[Email/MUA|mail user agent]]. It also supports [[Email/LMTP|LMTP]].

<<TableOfContents>>

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== Installation ==

Most [[Linux]] and [[BSD]] distributions offer a `dovecot` package.

For systemd-capable systems, start and enable `dovecot.service`.

For BSD distributions, try:

{{{
service dovecot start
}}}

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== Configuration ==

`dovecot(1)` is primarily configured in `/etc/dovecot/dovecot.conf` (or `/usr/local/etc/dovecot/dovecot.conf` for [[BSD|BSDs]]).

A basic configuration looks like:

{{{
protocols = imap pop3
pop3_uidl_format = %g
ssl = no
disable_plaintext_auth = no

log_path = /var/log/dovecot.log
mail_location = maildir:~/Maildir

auth_verbose = yes
auth_mechanisms = plain
passdb {
  driver = pam
}
userdb {
  driver = passwd
  args = blocking=no
  override_fields = uid=vmail gid=vmail
}
}}}

For almost any configuration, it is necessary to have a `vmail` system user.

{{{
sudo groupadd -g 5000 vmail
sudo useradd -u 5000 -g vmail -s /usr/bin/nologin -d /var/vmail -m vmail

sudo touch /var/log/dovecot.log
sudo chown vmail:vmail /var/log/dovecot.log
}}}

To test a configuration file, try `dovecot -n`.



=== Default Folder ===

By default, `dovecot(1)` expects several folders to exist. This can propogate confusing error messages. `dovecot(1)` can be configured to automatically create them as needed.

{{{
namespace inbox {
  mailbox Drafts {
    special_use = \Drafts
    auto = create
  }
  mailbox Junk {
    special_use = \Junk
    auto = create
  }
  mailbox Trash {
    special_use = \Trash
    auto = create
  }
  mailbox Sent {
    special_use = \Sent
    auto = create
  }
}
}}}



=== Encryption ===

{{{
ssl = yes
disable_plaintext_auth = yes
ssl_key = </usr/local/etc/letsencrypt/live/mail.example.com/privkey.pem
ssl_cert = </usr/local/etc/letsencrypt/live/mail.example.com/fullchain.pem
}}}



=== Local Users ===

The basic configuration for using local user authentication is:

{{{
passdb {
  driver = pam
}
}}}

This causes `/etc/pam.d/dovecot` to be used. This should look like:

{{{
auth      required        pam_unix.so nullok
account   required        pam_unix.so
}}}

If a different service file should be read, specify that service name like:

{{{
passdb {
  driver = pam
  args = foobar
}
}}}

If a protocol-dependent service file should be read, i.e. `/etc/pam.d/imap` for [[Email/IMAP|IMAP]] and `/etc/pam.d/pop` for [[Email/POP|POP]], try:

{{{
passdb {
  driver = pam
  args = %s
}
}}}



=== Virtual Users ===

To handle mail for '''virtual users''' who do not correspond to local users, try:

{{{
mail_home = /var/vmail/%n
mail_location = maildir:~/mail

passdb {
  driver = passwd-file
  args = /etc/dovecot/passwd
}
userdb {
  driver = static
  args = uid=vmail gid=vmail home=/home/vmail/%n
}
}}}

`%n` is substituted with the user part of the recipient address. `%d` would be substituted with the domain part, if there is one. `%u` would be substitued with the entire address.

The `passwd-file` file should look like:

{{{
alice:{PLAIN}pass::::::
bob:{PLAIN}secret::::::
charlie@example.com:{PLAIN}hello123::::::
dave@elsewhere.com:{SSHA256}ZpgszeowIcHdoxe3BNqvUTtPxFd6fMsyQxEWyY0Qlobaacjk
}}}

The `{SSHA256}`-encrypted password would be created by interactively running `doveadm pw -s ssha256`.



=== LMTP ===

To also use `dovecot(1)` as an [[Email/LMTP|LMTP]] server, try:

{{{
protocols = imap pop3 lmtp

service lmtp {
   inet_listener lmtp {
      address = 127.0.0.1
      port = 24
   }
  }
}
}}}

If this is not configured, `dovecot(1)` is ''not going to deliver mail for users''. It falls on the external [[Email/SMTP|SMTP]] server to handle it, even though it is using `dovecot(1)` for authentication.

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== See also ==

[[https://man.archlinux.org/man/dovecot.1|dovecot(1)]]

[[https://doc.dovecot.org/|Dovecot manual]]



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CategoryRicottone