Dovecot with imap, starttls, ldap authentication, sieve rules in ldap.

Uses SSMTP to send mails (for example if you have a redirect sieve rule).

Volumes

• /var/lib/vmail/mail
• /etc/ssl/mail:ro: certificates have to be here.

Environment Variables

HOSTNAME

Fully qualified name of the mail host.

SSMTP_MAIL_RELAY

Hostname and port for the used smtp relay (for example mail.example.com:587).

SSMTP_USER

User to authenticate agains the smtp relay.

SSMTP_PASSWORD

Password to authenticate agains the smtp relay.

SSMTP_AUTH_METHOD

• default: LOGIN

Which authentication mechanism to use for the smtp relay.

SSMTP_USE_STARTTLS

• default: yes

Whether to use starttls for the smtp relay.

LDAP_HOST

Ldap hostname (can include the port).

LDAP_SIEVE_HOST

Has to be the same as LDAP_URI but in a different format (like ldap:389).

LDAP_BIND_DN

DN used to authenticate against ldap.

LDAP_BIND_PASSWORD

Password used to authenticate against ldap.

LDAP_BASE_DN

Base DN to look for users on the ldap host.

LDAP_SCOPE

• default: subtree

Search scope of ldap queries.

LDAP_PASS_FILTER

Specifies the filter on how user is found on the ldap host. Dovecot variables can be used.

LDAP_USER_ATTRIBUTE

• default: cn

The ldap attribute which stands for the username.

LDAP_PASSWORD_ATTRIBUTE

• default: userPassword

The ldap attribute which stands for the password.

LDAP_SIEVE_ATTRIBUTE

• default: sieve

The ldap attribute which contains the sieve rules.

LDAP_USE_TLS

• default: yes

Whether to use tls when connecting to the ldap host.

LDAP_APP_PASSWORDS_BASE_DN

Base DN to look for app passwords for a user.

LDAP_APP_PASSWORDS_FILTER

Specifies the filter on what counts as an app password.

ALLOWED_USERNAME_CHARS

• default: äöüabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@

List of characters allowed in a username.

AUTH_MECHANISMS

• default: plain

Space seperated list of supported authentication mechanisms.

CERT_DOMAIN

Name of the certificate domain.

SSL_DH_LENGTH

• default: 2048

Length of the Diffie-Helman key in bits.

SSL_MIN_PROTOCOL

• default: TLSv1.2

Ssl minimum protocol version.

SSL_CIPHERLIST

• default: ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256

Colon seperated list of supported ciphers (!disables a cipher).

Go here for a list of ciphers.

IMAP_MAX_USER_CONNECTIONS

• default: 10

Maximum number of connections from the same user + ip.

Ports

• 143

Capabilities

• CHOWN
• DAC_OVERRIDE
• FOWNER
• NET_BIND_SERVICE
• SETGID
• SETUID
• SYS_CHROOT