### auth/30_exim4-config_examples
#################################

# The examples below are for server side authentication, when the
# local exim is SMTP server and clients authenticate to the local exim.

# They allow two styles of plain-text authentication against an
# CONFDIR/passwd file whose syntax is described in exim4_passwd(5).

# Hosts that are allowed to use AUTH are defined by the
# auth_advertise_hosts option in the main configuration. The default is
# "*", which allows authentication to all hosts over all kinds of
# connections if there is at least one authenticator defined here.
# Authenticators which rely on unencrypted clear text passwords don't
# advertise on unencrypted connections by default. Thus, it might be
# wise to set up TLS to allow encrypted connections. If TLS cannot be
# used for some reason, you can set AUTH_SERVER_ALLOW_NOTLS_PASSWORDS to
# advertise unencrypted clear text password based authenticators on all
# connections. As this is severely reducing security, using TLS is
# preferred over allowing clear text password based authenticators on
# unencrypted connections.

# PLAIN authentication has no server prompts. The client sends its
# credentials in one lump, containing an authorization ID (which we do not
# use), an authentication ID, and a password. The latter two appear as
# $auth2 and $auth3 in the configuration and should be checked against a
# valid username and password. In a real configuration you would typically
# use $auth2 as a lookup key, and compare $auth3 against the result of the
# lookup, perhaps using the crypteq{}{} condition.

# plain_server:
#   driver = plaintext
#   public_name = PLAIN
#   server_condition = "${if crypteq{$auth3}{${extract{1}{:}{${lookup{$auth2}lsearch{CONFDIR/passwd}{$value}{*:*}}}}}{1}{0}}"
#   server_set_id = $auth2
#   server_prompts = :
#   .ifndef AUTH_SERVER_ALLOW_NOTLS_PASSWORDS
#   server_advertise_condition = ${if eq{$tls_in_cipher}{}{}{*}}
#   .endif

# LOGIN authentication has traditional prompts and responses. There is no
# authorization ID in this mechanism, so unlike PLAIN the username and
# password are $auth1 and $auth2. Apart from that you can use the same
# server_condition setting for both authenticators.

# login_server:
#   driver = plaintext
#   public_name = LOGIN
#   server_prompts = "Username:: : Password::"
#   server_condition = "${if crypteq{$auth2}{${extract{1}{:}{${lookup{$auth1}lsearch{CONFDIR/passwd}{$value}{*:*}}}}}{1}{0}}"
#   server_set_id = $auth1
#   .ifndef AUTH_SERVER_ALLOW_NOTLS_PASSWORDS
#   server_advertise_condition = ${if eq{$tls_in_cipher}{}{}{*}}
#   .endif
#
# cram_md5_server:
#   driver = cram_md5
#   public_name = CRAM-MD5
#   server_secret = ${extract{2}{:}{${lookup{$auth1}lsearch{CONFDIR/passwd}{$value}fail}}}
#   server_set_id = $auth1

# Here is an example of CRAM-MD5 authentication against PostgreSQL:
#
# psqldb_auth_server:
#   driver = cram_md5
#   public_name = CRAM-MD5
#   server_secret = ${lookup pgsql{SELECT pw FROM users WHERE username = '${quote_pgsql:$auth1}'}{$value}fail}
#   server_set_id = $auth1

# Authenticate against local passwords using sasl2-bin
# Requires exim_uid to be a member of sasl group, see README.Debian.gz
# plain_saslauthd_server:
#   driver = plaintext
#   public_name = PLAIN
#   server_condition = ${if saslauthd{{$auth2}{$auth3}}{1}{0}}
#   server_set_id = $auth2
#   server_prompts = :
#   .ifndef AUTH_SERVER_ALLOW_NOTLS_PASSWORDS
#   server_advertise_condition = ${if eq{$tls_in_cipher}{}{}{*}}
#   .endif
#
# login_saslauthd_server:
#   driver = plaintext
#   public_name = LOGIN
#   server_prompts = "Username:: : Password::"
#   # don't send system passwords over unencrypted connections
#   server_condition = ${if saslauthd{{$auth1}{$auth2}}{1}{0}}
#   server_set_id = $auth1
#   .ifndef AUTH_SERVER_ALLOW_NOTLS_PASSWORDS
#   server_advertise_condition = ${if eq{$tls_in_cipher}{}{}{*}}
#   .endif
#
# ntlm_sasl_server:
#   driver = cyrus_sasl
#   public_name = NTLM
#   server_realm = <short main hostname>
#   server_set_id = $auth1
#   .ifndef AUTH_SERVER_ALLOW_NOTLS_PASSWORDS
#   server_advertise_condition = ${if eq{$tls_in_cipher}{}{}{*}}
#   .endif
# 
# digest_md5_sasl_server:
#   driver = cyrus_sasl
#   public_name = DIGEST-MD5
#   server_realm = <short main hostname>
#   server_set_id = $auth1
#   .ifndef AUTH_SERVER_ALLOW_NOTLS_PASSWORDS
#   server_advertise_condition = ${if eq{$tls_in_cipher}{}{}{*}}
#   .endif

# Authentcate against cyrus-sasl
# This is mainly untested, please report any problems to
# pkg-exim4-users@lists.alioth.debian.org.
# cram_md5_sasl_server:
#   driver = cyrus_sasl
#   public_name = CRAM-MD5
#   server_realm = <short main hostname>
#   server_set_id = $auth1
#
# plain_sasl_server:
#   driver = cyrus_sasl
#   public_name = PLAIN
#   server_realm = <short main hostname>
#   server_set_id = $auth1
#   .ifndef AUTH_SERVER_ALLOW_NOTLS_PASSWORDS
#   server_advertise_condition = ${if eq{$tls_in_cipher}{}{}{*}}
#   .endif
#
# login_sasl_server:
#   driver = cyrus_sasl
#   public_name = LOGIN
#   server_realm = <short main hostname>
#   server_set_id = $auth1
#   .ifndef AUTH_SERVER_ALLOW_NOTLS_PASSWORDS
#   server_advertise_condition = ${if eq{$tls_in_cipher}{}{}{*}}
#   .endif

# Authenticate against courier authdaemon

# This is now the (working!) example from
# http://www.exim.org/eximwiki/FAQ/Policy_controls/Q0730
# Possible pitfall: access rights on /run/courier/authdaemon/socket.
# plain_courier_authdaemon:
#   driver = plaintext
#   public_name = PLAIN
#   server_condition = \
#     ${extract {ADDRESS} \
#               {${readsocket{/run/courier/authdaemon/socket} \
#               {AUTH ${strlen:exim\nlogin\n$auth2\n$auth3\n}\nexim\nlogin\n$auth2\n$auth3\n} }} \
#               {yes} \
#               fail}
#   server_set_id = $auth2
#   .ifndef AUTH_SERVER_ALLOW_NOTLS_PASSWORDS
#   server_advertise_condition = ${if eq{$tls_in_cipher}{}{}{*}}
#   .endif

# login_courier_authdaemon:
#   driver = plaintext
#   public_name = LOGIN
#   server_prompts = Username:: : Password::
#   server_condition = \
#     ${extract {ADDRESS} \
#               {${readsocket{/run/courier/authdaemon/socket} \
#               {AUTH ${strlen:exim\nlogin\n$auth1\n$auth2\n}\nexim\nlogin\n$auth1\n$auth2\n} }} \
#               {yes} \
#               fail}
#   server_set_id = $auth1
#   .ifndef AUTH_SERVER_ALLOW_NOTLS_PASSWORDS
#   server_advertise_condition = ${if eq{$tls_in_cipher}{}{}{*}}
#   .endif

# This one is a bad hack to support the broken version 4.xx of
# Microsoft Outlook Express which violates the RFCs by demanding
# "250-AUTH=" instead of "250-AUTH ".
# If your list of offered authenticators is other than PLAIN and LOGIN,
# you need to adapt the public_name line manually.
# It has to be the last authenticator to work and has not been tested
# well. Use at your own risk.
# See the thread entry point from
# http://www.exim.org/mail-archives/exim-users/Week-of-Mon-20050214/msg00213.html
# for the related discussion on the exim-users mailing list.
# Thanks to Fred Viles for this great work.

# support_broken_outlook_express_4_server:
#   driver = plaintext
#   public_name = "\r\n250-AUTH=PLAIN LOGIN"
#   server_prompts = User Name : Password
#   server_condition = no
#   .ifndef AUTH_SERVER_ALLOW_NOTLS_PASSWORDS
#   server_advertise_condition = ${if eq{$tls_in_cipher}{}{}{*}}
#   .endif

# Use dovecot as authentication backend
# Requires changes to dovecot configuration:
# 8X---------------------
# --- /etc/dovecot/conf.d/10-master.conf    2020-12-22 13:26:52.000000000 +0000
# +++ /etc/dovecot/conf.d/10-master.conf 2022-07-13 11:17:02.479100984 +0000
# @@ -108,6 +108,14 @@
#    #  mode = 0666
#    #}
#
# +### SASL listener for exim start
# +  # SASL exim
# +  unix_listener /var/spool/exim4/dovecot.auth-client {
# +     mode = 0660
# +     group = Debian-exim
# +  }
# +### SASL listener for exim end
# +
#    # Auth process is run as this user.
#    #user = $default_internal_user
#  }
# 8X---------------------
#
# dovecot_plain_server:
#   driver = dovecot
#   public_name = PLAIN
#   server_socket = /var/spool/exim4/dovecot.auth-client
#   server_set_id = $auth1

##############
# See /usr/share/doc/exim4-base/README.Debian.gz
##############

# These examples below are the equivalent for client side authentication.
# They get the passwords from CONFDIR/passwd.client, whose format is
# defined in exim4_passwd_client(5)

# Because AUTH PLAIN and AUTH LOGIN send the password in clear, we
# only allow these mechanisms over encrypted connections by default.
# You can set AUTH_CLIENT_ALLOW_NOTLS_PASSWORDS to allow unencrypted
# clear text password authentication on all connections.

cram_md5:
  driver = cram_md5
  public_name = CRAM-MD5
  client_name = ${extract{1}{:}{${lookup{$host}nwildlsearch{CONFDIR/passwd.client}{$value}fail}}}
  client_secret = ${extract{2}{:}{${lookup{$host}nwildlsearch{CONFDIR/passwd.client}{$value}fail}}}

# this returns the matching line from passwd.client and doubles all ^
PASSWDLINE=${sg{\
                ${lookup{$host}nwildlsearch{CONFDIR/passwd.client}{$value}fail}\
	        }\
	        {\\N[\\^]\\N}\
	        {^^}\
	    }

plain:
  driver = plaintext
  public_name = PLAIN
.ifndef AUTH_CLIENT_ALLOW_NOTLS_PASSWORDS
  client_send = "<; ${if !eq{$tls_out_cipher}{}\
                    {^${extract{1}{:}{PASSWDLINE}}\
		     ^${sg{PASSWDLINE}{\\N([^:]+:)(.*)\\N}{\\$2}}\
		   }fail}"
.else
  client_send = "<; ^${extract{1}{:}{PASSWDLINE}}\
		    ^${sg{PASSWDLINE}{\\N([^:]+:)(.*)\\N}{\\$2}}"
.endif

login:
  driver = plaintext
  public_name = LOGIN
.ifndef AUTH_CLIENT_ALLOW_NOTLS_PASSWORDS
  # Return empty string if not non-TLS AND looking up $host in passwd-file
  # yields a non-empty string; fail otherwise.
  client_send = "<; ${if and{\
                          {!eq{$tls_out_cipher}{}}\
                          {!eq{PASSWDLINE}{}}\
                         }\
                      {}fail}\
                 ; ${extract{1}{::}{PASSWDLINE}}\
		 ; ${sg{PASSWDLINE}{\\N([^:]+:)(.*)\\N}{\\$2}}"
.else
  # Return empty string if looking up $host in passwd-file yields a
  # non-empty string; fail otherwise.
  client_send = "<; ${if !eq{PASSWDLINE}{}\
                      {}fail}\
                 ; ${extract{1}{::}{PASSWDLINE}}\
		 ; ${sg{PASSWDLINE}{\\N([^:]+:)(.*)\\N}{\\$2}}"
.endif