Dovecot /

Install Dovecot (Maildir)

Dovecot is a free and open source IMAP and POP3 server. This guide will setup Dovecot to use the Maildir format, pairing nicely with the OpenSMTPd Maildir guide. This guide will allow users to read mail with IMAP and POP.

Installation

Dovecot is third-party software available in [pkgadd/usage|packages]]:

# pkg_add dovecot--

This will install the flavor of dovecot without gssapi.

Configuration

In /etc/dovecot/dovecot.conf, add the following lines at the bottom of the file:

protocols = imap pop3
listen = 198.51.100.2, 2001:db8::2

Replace 198.51.100.2 and 2001:db8::2 with the server's actual public IP addresses. This tells dovecot to listen to the protocols IMAP and POP3. Note: Neither LMTP nor submission are required.

No changes need to be made to /etc/dovecot/conf.d/10-auth.conf. By default, the OpenBSD package will use the system passwd(5) file for authentication.

In /etc/dovecot/conf.d/10-mail.conf, add this line:

mail_location = maildir:%h/Maildir

This indicates to dovecot that all mail is stored in users' home folders, ~/Maildir.

In /etc/dovecot/conf.d/10-ssl.conf, change the following lines:

ssl = yes
...
ssl_cert = </etc/ssl/example.com.crt
ssl_key = </etc/ssl/private/example.com.key

Replace example.com with the actual domain.

IMAP mailboxes

Some directories such as "Sent" are not shown to users by default unless the user subscribes to it. if you want this happen automatically, you may add the following to /etc/dovecont/conf.d/15-mailboxes.conf, for each mailbox you seem fit:

    auto = subscribe

For example, to automatically subscribe to Drafts directory:

  mailbox Drafts {
    auto = subscribe
    special_use = \Drafts
  }

Dump non-default settings

Dovecot can dump all non-default settings. Verify that the non-default settings are similar to those listed below:

$ doas dovecot -n
# 2.3.21.1 (d492236fa0): /etc/dovecot/dovecot.conf
# OS: OpenBSD 7.7 amd64
# Hostname: telecomm5.my.domain
first_valid_uid = 1000
mail_location = maildir:%h/Maildir
mbox_write_locks = fcntl
mmap_disable = yes
namespace inbox {
  inbox = yes
  location =
  mailbox Drafts {
    auto = subscribe
    special_use = \Drafts
  }
  mailbox Junk {
    auto = subscribe
    special_use = \Junk
  }
  mailbox Sent {
    auto = subscribe
    special_use = \Sent
  }
  mailbox Trash {
    auto = subscribe
    special_use = \Trash
  }
  prefix =
}
passdb {
  driver = bsdauth
}
protocols = imap pop3
ssl_cert = </etc/ssl/telecomm.crt
ssl_key = # hidden, use -P to show it
userdb {
  driver = passwd
}

Login classes

After installation, the package will provide a README in /usr/local/share/doc/pkg-readmes/dovecot.

Dovecot automatically adds a capability database in /etc/login.conf.d/dovecot:

dovecot:\
	:openfiles-cur=1024:\
	:openfiles-max=2048:\
	:tc=daemon:

This login class gives dovecot special permissions. On a large server, it may be necessary to further increase the permissions. This can help if the server has many public IP addresses:

dovecot:\
	:openfiles-cur=4096:\
	:openfiles-max=8192:\
	:tc=daemon:

See the login class guide for further information on login classes.

Starting dovecot

To start dovecot via rcctl:

# rcctl enable dovecot
# rcctl start dovecot

Troubleshooting Dovecot

See the dovecot troubleshooting guide.