IMAP4rev1 endpoint

Module 'imap' is a listener that implements IMAP4rev1 protocol and provides access to local messages storage specified by 'storage' directive.

In most cases, local storage modules will auto-create accounts when they are accessed via IMAP. This relies on authentication provider used by IMAP endpoint to provide what essentially is access control. There is a caveat, however: this auto-creation will not happen when delivering incoming messages via SMTP as there is no authentication to confirm that this account should indeed be created.

Configuration directives

imap tcp:// tls:// {
    tls /etc/ssl/private/cert.pem /etc/ssl/private/pkey.key
    io_debug no
    debug no
    insecure_auth no
    auth pam
    storage &local_mailboxes
    auth_map identity
    auth_map_normalize auto
    storage_map identity
    storage_map_normalize auto

tls certificate-path key-path { ... }

Default: global directive value

TLS certificate & key to use. Fine-tuning of other TLS properties is possible by specifying a configuration block and options inside it:

tls cert.crt key.key {
    protocols tls1.2 tls1.3

See TLS configuration / Server for details.

io_debug boolean

Default: no

Write all commands and responses to stderr.

io_errors boolean

Default: no

Log I/O errors.

debug boolean

Default: global directive value

Enable verbose logging.

insecure_auth boolean

Default: no (yes if TLS is disabled)

auth module-reference


Use the specified module for authentication.

storage module-reference


Use the specified module for message storage.

storage_map module-reference

Default: identity

Use the specified table to map SASL usernames to storage account names.

Before username is looked up, it is normalized using function defined by storage_map_normalize.

This directive is useful if you want users and to share the same storage account named "user". In this case, use

    storage_map email_localpart

Note that storage_map does not affect the username passed to the authentication provider.

It also does not affect how message delivery is handled, you should specify delivery_map in storage module to define how to map email addresses to storage accounts. E.g.

    storage.imapsql local_mailboxes {
        delivery_map email_localpart # deliver "user@*" to mailbox for "user"

storage_map_normalize function

Default: auto

Same as auth_map_normalize but for storage_map.

auth_map_normalize function

Default: auto

Overrides global auth_map_normalize value for this endpoint.

See Global configuration for details.