dovecot container

Dovecot is an open source IMAP and POP3 email server. It is an excellent choice for both small and large installations. It's fast, simple to set up, requires no special administration and it uses very little memory.

• Guide
• Run a new dovecot instance
• Data persistence
• TLS
• Auto-generated certificate
• Own certificate
• Disable TLS
• Supported environment variables
• Generic variables
• Variables for TLS
• Variables for LDAP
• Various configuration variables
• Data persistence volumes

Guide

Run a new dovecot instance

This dovecot container will create and setup the configuration files at every restart, but it is also possible to provide an own set of configuration files.

The command to run this container is:

podman run -d --rm --name dovecot -p 110:110 -p 143:143 -p 993:993 -p 995:995 -e USE_LDAP=1 -e LDAP_BASE_DN="ou=mail,dc=example,dc=org" -e LDAP_BIND_DN="cn=mailAccountReader,ou=Manager,dc=example,dc=org" -e LDAP_BIND_PASSWORD="password" registry.opensuse.org/opensuse/dovecot

Data persistence

There are some directories to store persistence data like /var/spool/vmail for the emails and /etc/certs for the certificates.

If the UID and GID of the vmail user, which owns the /var/spool/vmail hierachy, needs to match in the container and in the host, the VMAIL_UID environment variable needs to be set explicitly. This variable needs to match the postfix container VMAIL_UID variable.

TLS

Auto-generated certificate

TLS is be configured and enabled by default. If no certificate is provided, a self-signed one is created during container startup for the container hostname. The hostname for the certificate can be set e.g. by podman run -e HOSTNAME=ldap.example.org ...

Own certificate

You can set your custom certificate at run time, by mounting a volume with the certificates into the container and adjusting the following environment variables:

podman run -v /srv/dovecot/certs:/etc/certs:Z \
       -e DOVECOT_TLS_CRT=/etc/certs/dovecot.crt \
       -e DOVECOT_TLS_KEY=/etc/certs/dovecot.key \
       -e DOVECOT_TLS_CA_CRT=/etc/certs/ca.crt \
       -d registry.opensuse.org/opensuse/dovecot:latest

Disable TLS

Add --env DOVECOT_TLS=0 to the run command: podman run -e DOVECOT_TLS=0 ...

Supported environment variables:

Generic variables:

• DEBUG=[0|1] Enables "set -x" in the entrypoint script
• TZ Timezone to use in the container

Variables for TLS:

• DOVECOT_TLS=[1|0] Enable TLS. Defaults to 1 (true).
• DOVECOT_TLS_CA_CRT Dovecot ssl CA certificate. Defaults to /etc/certs/dovecot-ca.crt.
• DOVECOT_TLS_CA_KEY Private dovecot CA key. Defaults to /etc/certs/dovecot-ca.key.
• DOVECOT_TLS_CRT Dovecot ssl certificate. Defaults to /etc/certs/dovecot-tls.crt.
• DOVECOT_TLS_KEY Private dovecot ssl key. Defaults to /etc/certs/dovecot-tls.key.
• DOVECOT_TLS_DH_PARAM Dovecot ssl certificate dh param file.
• DOVECOT_TLS_ENFORCE=[0|1] Enforce TLS but except ldapi connections. Defaults to 0 (false).
• DOVECOT_TLS_CIPHER_SUITE TLS cipher suite.

Variables for LDAP

• USE_LDAP=[0|1] Use LDAP for user database
• LDAP_HOSTS Hosts running ldap server
• LDAP_BASE_DN Ldap base DN to look for accounts. Defaults to ou=mail,dc=example,dc=org
• LDAP_BIND_DN DN used to read user account data. Defaults tocn=mailAccountReader,ou=Manager,dc=example,dc=org`
• LDAP_BIND_PASSWORD Password for LDAP_BIND_DN.
• LDAP_USE_TLS=[0|1] Use TLS for LDAP queries, defaults to 1
• LDAP_TLS_CA_CRT LDAP CA certificate to verify connections.

Various configuration variables:

• USE_VMAIL_USER=1 Enable VMAIL user, defaults to 1
• VMAIL_UID=5000 UID/GID of vmail user. All files in /var/spool/vmail will be changed to this UID/GID
• ENABLE_IMAP=[0|1] Enables imap support, defaults to 1
• ENABLE_POP3=[0|1] Enables pop3 support, defaults to 0
• ENABLE_LMTP=[0|1] Enables mail delivery via LMTP, defaults to 0
• ENABLE_SIEVE=[0|1] Enables sieve support if LMTP is enabled, defaults to 1
• ENABLE_MANAGESIEVE=[0|1] Enables ManageSieve, requires to export Port 4190. Only available if ENABLE_LMTP and ENABLE_SIEVE are set to 1. Defaults to 0

Data persistence volumes

• /var/spool/vmail Mail storage
• /etc/certs TLS certificates for dovecot
• /etc/dovecot User supplied dovecot configuration files