This documentation is for Dovecot v2.x, see wiki1 for v1.x documentation.

Login referrals

Login referrals are an IMAP extension specified by RFC 2221. They're not supported by many clients, so you probably don't want to use them normally.

Login referrals can be used in two ways:

  1. Tell the client to log into another server without allowing to log in locally.
  2. Suggest the client to log into another server, but log it in anyway.

The following fields can be used to configure login referrals:

Using the above settings you can suggest client to log in elsewhere. To require it, you'll also have to return:

Client support

The following clients are known to support login referrals:


Forward user to another server after successful authentication:

password_query = SELECT password, host, 'Y' as nologin FROM users WHERE userid = '%u' 

Forward all users to another server without authentication:

# NOTE: '\' line splitting is used only for readability, currently Dovecot doesn't support it
password_query = \
  SELECT NULL AS password, \
  '' AS host, \
  'This server is down, try another one.' AS reason, \
  'Y' as nologin, \
  'Y' as nodelay