# When a user other than root uses the -C option to override the configuration
# file (including the Exim user when re-executing Exim to regain root
# privileges for local message delivery), this will normally cause Exim to
-# drop root privileges. The TRUSTED_CONFIG_PREFIX_LIST option, specifies
-# a file which contains a list of trusted configuration prefixes (like the
-# ALT_CONFIG_PREFIX above), one per line. If the -C option is used to specify
-# a configuration file which matches a trusted prefix, root privileges are not
-# dropped by Exim.
+# drop root privileges. The TRUSTED_CONFIG_LIST option, specifies a file which
+# contains a list of trusted configuration filenames, one per line. If the -C
+# option is used by the Exim user or by the user specified in the
+# CONFIGURE_OWNER setting, to specify a configuration file which is listed in
+# the TRUSTED_CONFIG_LIST file, then root privileges are not dropped by Exim.
-# TRUSTED_CONFIG_PREFIX_LIST=/usr/exim/trusted_configs
+# TRUSTED_CONFIG_LIST=/usr/exim/trusted_configs
#------------------------------------------------------------------------------
# DISABLE_D_OPTION=yes
+#------------------------------------------------------------------------------
+# By contrast, you might be maintaining a system which relies upon the ability
+# to override values with -D and assumes that these will be passed through to
+# the delivery processes. As of Exim 4.73, this is no longer the case by
+# default. Going forward, we strongly recommend that you use a shim Exim
+# configuration file owned by root stored under TRUSTED_CONFIG_PREFIX_LIST.
+# That shim can set macros before .include'ing your main configuration file.
+#
+# As a strictly transient measure to ease migration to 4.73, the
+# WHITELIST_D_MACROS value definies a colon-separated list of macro-names
+# which are permitted to be overriden from the command-line which will be
+# honoured by the Exim user. So these are macros that can persist to delivery
+# time.
+# Examples might be -DTLS or -DSPOOL=/some/dir. The values on the
+# command-line are filtered to only permit: [A-Za-z0-9_/.-]*
+#
+# This option is highly likely to be removed in a future release. It exists
+# only to make 4.73 as easy as possible to migrate to. If you use it, we
+# encourage you to schedule time to rework your configuration to not depend
+# upon it. Most people should not need to use this.
+#
+# By default, no macros are whitelisted for -D usage.
+
+# WHITELIST_D_MACROS=TLS:SPOOL
+
#------------------------------------------------------------------------------
# Exim has support for the AUTH (authentication) extension of the SMTP
# protocol, as defined by RFC 2554. If you don't know what SMTP authentication