2. Use the following global settings to configure DMARC:
-Required:
+Optional:
dmarc_tld_file Defines the location of a text file of valid
top level domains the opendmarc library uses
during domain parsing. Maintained by Mozilla,
the most current version can be downloaded
from a link at http://publicsuffix.org/list/.
+ If unset, "/etc/exim/opendmarc.tlds" (hardcoded)
+ is used.
Optional:
dmarc_history_file Defines the location of a file to log results
in combination with EXPERIMENTAL_EVENT), and a new variable
$tls_out_tlsa_usage (detailed above).
+Under GnuTLS, DANE is only supported from versin 3.0.0 onwards
+
DSN extra information