##
## Authentication processes
##

# Authentication cache size in kilobytes. 0 means it's disabled.
# Note that bsdauth, PAM and vpopmail require cache_key to be set for caching
# to be used.
#auth_cache_size = 0
# Time to live in seconds for cached data. After this many seconds the cached
# record is no longer used, *except* if the main database lookup returns
# internal failure. We also try to handle password changes automatically: If
# user's previous authentication was successful, but this one wasn't, the
# cache isn't used. For now this works only with plaintext authentication.
#auth_cache_ttl = 3600
# TTL for negative hits (user not found). 0 disables caching them completely.
#auth_cache_negative_ttl = 3600

# Space separated list of realms for SASL authentication mechanisms that need
# them. You can leave it empty if you don't want to support multiple realms.
# Many clients simply use the first one listed here, so keep the default realm
# first.
#auth_realms =

# Default realm/domain to use if none was specified. This is used for both
# SASL realms and appending @domain to username in plaintext logins.
#auth_default_realm = 

# List of allowed characters in username. If the user-given username contains
# a character not listed in here, the login automatically fails. This is just
# an extra check to make sure user can't exploit any potential quote escaping
# vulnerabilities with SQL/LDAP databases. If you want to allow all characters,
# set this value to empty.
#auth_username_chars = abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@

# Username character translations before it's looked up from databases. The
# value contains series of from -> to characters. For example "#@/@" means
# that '#' and '/' characters are translated to '@'.
#auth_username_translation =

# Username formatting before it's looked up from databases. You can use
# the standard variables here, eg. %Lu would lowercase the username, %n would
# drop away the domain if it was given, or "%n-AT-%d" would change the '@' into
# "-AT-". This translation is done after auth_username_translation changes.
#auth_username_format =

# If you want to allow master users to log in by specifying the master
# username within the normal username string (ie. not using SASL mechanism's
# support for it), you can specify the separator character here. The format
# is then <username><separator><master username>. UW-IMAP uses "*" as the
# separator, so that could be a good choice.
#auth_master_user_separator =

# Username to use for users logging in with ANONYMOUS SASL mechanism
#auth_anonymous_username = anonymous

# Maximum number of dovecot-auth worker processes. They're used to execute
# blocking passdb and userdb queries (eg. MySQL and PAM). They're
# automatically created and destroyed as needed.
#auth_worker_max_count = 30

# Host name to use in GSSAPI principal names. The default is to use the
# name returned by gethostname(). Use "$ALL" to allow all keytab entries.
#auth_gssapi_hostname =

# Kerberos keytab to use for the GSSAPI mechanism. Will use the system 
# default (usually /etc/krb5.keytab) if not specified.
#auth_krb5_keytab = 

# Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon and
# ntlm_auth helper. <doc/wiki/Authentication/Mechanisms/Winbind.txt>
#auth_use_winbind = no

# Path for Samba's ntlm_auth helper binary.
#auth_winbind_helper_path = /usr/bin/ntlm_auth

# Number of seconds to delay before replying to failed authentications.
#auth_failure_delay = 2

auth default {
  # Space separated list of wanted authentication mechanisms:
  #   plain login digest-md5 cram-md5 ntlm rpa apop anonymous gssapi otp skey
  #   gss-spnego
  # NOTE: See also disable_plaintext_auth setting.
  auth_mechanisms = plain

  #
  # Password database is used to verify user's password (and nothing more).
  # You can have multiple passdbs and userdbs. This is useful if you want to
  # allow both system users (/etc/passwd) and virtual users to login without
  # duplicating the system users into virtual database.
  #
  # <doc/wiki/PasswordDatabase.txt>
  #
  # By adding master=yes setting inside a passdb you make the passdb a list
  # of "master users", who can log in as anyone else. Unless you're using PAM,
  # you probably still want the destination user to be looked up from passdb
  # that it really exists. This can be done by adding pass=yes setting to the
  # master passdb. <doc/wiki/Authentication.MasterUsers.txt>

  # Users can be temporarily disabled by adding a passdb with deny=yes.
  # If the user is found from that database, authentication will fail.
  # The deny passdb should always be specified before others, so it gets
  # checked first. Here's an example:

  #passdb passwd-file {
    # File contains a list of usernames, one per line
    #args = /etc/dovecot.deny
    #deny = yes
  #}

  # PAM authentication. Preferred nowadays by most systems. 
  # Note that PAM can only be used to verify if user's password is correct,
  # so it can't be used as userdb. If you don't want to use a separate user
  # database (passwd usually), you can use static userdb.
  # REMEMBER: You'll need /etc/pam.d/dovecot file created for PAM
  # authentication to actually work. <doc/wiki/PasswordDatabase.PAM.txt>
  passdb pam {
    # [session=yes] [setcred=yes] [failure_show_msg=yes] [max_requests=<n>]
    # [cache_key=<key>] [<service name>]
    #
    # session=yes makes Dovecot open and immediately close PAM session. Some
    # PAM plugins need this to work, such as pam_mkhomedir.
    #
    # setcred=yes makes Dovecot establish PAM credentials if some PAM plugins
    # need that. They aren't ever deleted though, so this isn't enabled by
    # default.
    #
    # max_requests specifies how many PAM lookups to do in one process before
    # recreating the process. The default is 100, because many PAM plugins
    # leak memory.
    #
    # cache_key can be used to enable authentication caching for PAM
    # (auth_cache_size also needs to be set). It isn't enabled by default
    # because PAM modules can do all kinds of checks besides checking password,
    # such as checking IP address. Dovecot can't know about these checks
    # without some help. cache_key is simply a list of variables (see
    # doc/wiki/Variables.txt) which must match for the cached data to be used.
    # Here are some examples:
    #   %u - Username must match. Probably sufficient for most uses.
    #   %u%r - Username and remote IP address must match.
    #   %u%s - Username and service (ie. IMAP, POP3) must match.
    # 
    # The service name can contain variables, for example %Ls expands to
    # pop3 or imap.
    #
    # Some examples:
    #   args = session=yes %Ls
    #   args = cache_key=%u dovecot
    #args = dovecot
  }

  # System users (NSS, /etc/passwd, or similiar)
  # In many systems nowadays this uses Name Service Switch, which is
  # configured in /etc/nsswitch.conf. <doc/wiki/AuthDatabase.Passwd.txt>
  #passdb passwd {
    # [blocking=yes] - See userdb passwd for explanation
    #args = 
  #}

  # Shadow passwords for system users (NSS, /etc/shadow or similiar).
  # Deprecated by PAM nowadays.
  # <doc/wiki/PasswordDatabase.Shadow.txt>
  #passdb shadow {
    # [blocking=yes] - See userdb passwd for explanation
    #args = 
  #}

  # PAM-like authentication for OpenBSD.
  # <doc/wiki/PasswordDatabase.BSDAuth.txt>
  #passdb bsdauth {
    # [cache_key=<key>] - See cache_key in PAM for explanation.
    #args =
  #}

  # passwd-like file with specified location
  # <doc/wiki/AuthDatabase.PasswdFile.txt>
  #passdb passwd-file {
    # [scheme=<default password scheme>] [username_format=<format>]
    # <Path for passwd-file>
    #args = 
  #}

  # checkpassword executable authentication
  # NOTE: You will probably want to use "userdb prefetch" with this.
  # <doc/wiki/AuthDatabase.CheckPassword.txt>
  #passdb checkpassword {
    # Path for checkpassword binary
    #args = 
  #}

  # SQL database <doc/wiki/AuthDatabase.SQL.txt>
  #passdb sql {
    # Path for SQL configuration file, see doc/dovecot-sql-example.conf
    #args = 
  #}

  # LDAP database <doc/wiki/AuthDatabase.LDAP.txt>
  #passdb ldap {
    # Path for LDAP configuration file, see doc/dovecot-ldap-example.conf
    #args = 
  #}

  # vpopmail authentication <doc/wiki/AuthDatabase.VPopMail.txt>
  #passdb vpopmail {
    # [cache_key=<key>] - See cache_key in PAM for explanation.
    # [quota_template=<template>] - %q expands to Maildir++ quota
    #   (eg. quota_template=quota_rule=*:backend=%q)
    #args =
  #}

  #
  # User database specifies where mails are located and what user/group IDs
  # own them. For single-UID configuration use "static".
  #
  # <doc/wiki/UserDatabase.txt>
  #

  # "prefetch" user database means that the passdb already provided the
  # needed information and there's no need to do a separate userdb lookup.
  # This can be made to work with SQL and LDAP databases, see their example
  # configuration files for more information how to do it.
  # <doc/wiki/UserDatabase.Prefetch.txt>
  #userdb prefetch {
  #}

  # System users (NSS, /etc/passwd, or similiar). In many systems nowadays this
  # uses Name Service Switch, which is configured in /etc/nsswitch.conf.
  # <doc/wiki/AuthDatabase.Passwd.txt>
  userdb passwd {
    # [blocking=yes] - By default the lookups are done in the main dovecot-auth
    # process. This setting causes the lookups to be done in auth worker
    # proceses. Useful with remote NSS lookups that may block.
    # NOTE: Be sure to use this setting with nss_ldap or users might get
    # logged in as each others!
    #args = 
  }

  # passwd-like file with specified location
  # <doc/wiki/AuthDatabase.PasswdFile.txt>
  #userdb passwd-file {
    # [username_format=<format>] <Path for passwd-file>
    #args =
  #}

  # checkpassword executable user database lookup
  # <doc/wiki/AuthDatabase.CheckPassword.txt>
  #userdb checkpassword {
    # Path for checkpassword binary
    #args = 
  #}

  # static settings generated from template <doc/wiki/UserDatabase.Static.txt>
  #userdb static {
    # Template for the fields. Can return anything a userdb could normally
    # return. For example:
    #
    #  args = uid=500 gid=500 home=/var/mail/%u
    #
    # If you use deliver, it needs to look up users only from the userdb. This
    # of course doesn't work with static because there is no list of users.
    # Normally static userdb handles this by doing a passdb lookup. This works
    # with most passdbs, with PAM being the most notable exception. If you do
    # the user verification another way, you can add allow_all_users=yes to
    # the args in which case the passdb lookup is skipped.
    #
    #args =
  #}

  # SQL database <doc/wiki/AuthDatabase.SQL.txt>
  #userdb sql {
    # Path for SQL configuration file, see doc/dovecot-sql-example.conf
    #args = 
  #}

  # LDAP database <doc/wiki/AuthDatabase.LDAP.txt>
  #userdb ldap {
    # Path for LDAP configuration file, see doc/dovecot-ldap-example.conf
    #args = 
  #}

  # vpopmail <doc/wiki/AuthDatabase.VPopMail.txt>
  #userdb vpopmail {
  #}

  # Require a valid SSL client certificate or the authentication fails.
  #auth_ssl_require_client_cert = no

  # Take the username from client's SSL certificate, using 
  # X509_NAME_get_text_by_NID() which returns the subject's DN's
  # CommonName. 
  #auth_ssl_username_from_cert = no
}

# If you wish to use another authentication server than dovecot-auth, you can
# use connect sockets. They are assumed to be already running, Dovecot's master
# process only tries to connect to them. They don't need any other settings
# than the path for the master socket, as the configuration is done elsewhere.
# Note that the client sockets must exist in the login_dir.
#auth external {
#  socket connect {
#    master {
#      path = /var/run/dovecot/auth-master
#    }
#  }
#}