diff --git a/opendmarc/opendmarc-config.h b/opendmarc/opendmarc-config.h
index 1b781df..8398007 100644
--- a/opendmarc/opendmarc-config.h
+++ b/opendmarc/opendmarc-config.h
@@ -47,6 +47,7 @@ struct configdef dmarcf_config[] =
 	{ "RequiredHeaders",		CONFIG_TYPE_BOOLEAN,	FALSE },
 	{ "RejectFailures",		CONFIG_TYPE_BOOLEAN,	FALSE },
 	{ "RejectMultiValueFrom",	CONFIG_TYPE_BOOLEAN,	FALSE },
+	{ "RejectString",		CONFIG_TYPE_STRING,	FALSE },
 	{ "ReportCommand",		CONFIG_TYPE_STRING,	FALSE },
 	{ "Socket",			CONFIG_TYPE_STRING,	FALSE },
 	{ "SoftwareHeader",		CONFIG_TYPE_BOOLEAN,	FALSE },
diff --git a/opendmarc/opendmarc.c b/opendmarc/opendmarc.c
index a1e49ec..c28aedd 100644
--- a/opendmarc/opendmarc.c
+++ b/opendmarc/opendmarc.c
@@ -190,6 +190,7 @@ struct dmarcf_config
 	char *			conf_historyfile;
 	char *			conf_pslist;
 	char *			conf_ignorelist;
+	char *			conf_rejectstring;
 	char **			conf_trustedauthservids;
 	char **			conf_ignoredomains;
 	struct list *		conf_domainwhitelist;
@@ -1427,6 +1428,10 @@ dmarcf_config_load(struct config *data, struct dmarcf_config *conf,
 		                  &conf->conf_rejectfail,
 		                  sizeof conf->conf_rejectfail);
 
+		(void) config_get(data, "RejectString",
+						  &conf->conf_rejectstring,
+						  sizeof conf->conf_rejectstring);
+
 		(void) config_get(data, "RequiredHeaders",
 		                  &conf->conf_reqhdrs,
 		                  sizeof conf->conf_reqhdrs);
@@ -1635,6 +1640,36 @@ dmarcf_config_load(struct config *data, struct dmarcf_config *conf,
 
 	pthread_rwlock_unlock(&hash_lock);
 
+	if ( conf->conf_rejectstring == NULL ) {
+		conf->conf_rejectstring = DEFREJECTSTR;
+	} else {
+		/* Count occurrences of "%s" in RejectString */
+		int countocc = 0;
+		const char *tmp = conf->conf_rejectstring;
+		if (strstr(tmp, '%%')) {
+			snprintf(err, errlen, "%s: The RejectString contains a %%%% (escaped %%)!",
+				basedir);
+			return -1;
+		}
+		while(tmp = strstr(tmp, "%s"))
+		{
+			countocc++;
+			tmp++;
+		}
+		switch ( countocc ) {
+			case 0:
+				snprintf(err, errlen, "%s: The RejectString doesn't contain %%s!",
+					basedir);
+				return -1;
+			case 1:
+				break;
+			default:
+				snprintf(err, errlen, "%s: The RejectString contains %d occurences of %%s instead of one!",
+					basedir, countocc);
+				return -1;
+		}
+	}
+
 	return 0;
 }
 
@@ -3566,7 +3601,7 @@ mlfi_eom(SMFICTX *ctx)
 		    random() % 100 < pct)
 		{
 			snprintf(replybuf, sizeof replybuf,
-			         "rejected by DMARC policy for %s", pdomain);
+			         conf->conf_rejectstring, pdomain);
 
 			status = dmarcf_setreply(ctx, DMARC_REJECT_SMTP,
 			                         DMARC_REJECT_ESC, replybuf);
diff --git a/opendmarc/opendmarc.conf.5.in b/opendmarc/opendmarc.conf.5.in
index f6fd6b4..4b6df51 100644
--- a/opendmarc/opendmarc.conf.5.in
+++ b/opendmarc/opendmarc.conf.5.in
@@ -261,6 +261,13 @@ If set, messages with multiple addresses in the From: field of the message
 will be rejected unless all domain names in that field are the same.  They
 will otherwise be ignored by the filter (the default).
 
+.TP
+.I RejectString (string)
+This string describes the reason of reject at SMTP level.
+The message MUST contain the word "%s" once, which will be replaced by the
+RFC5322.From domain. Escaped "%" ("%%") are not allowed in this string.
+The default is "rejected by DMARC policy for %s"
+
 .TP
 .I ReportCommand (string)
 Indicates the shell command to which failure reports should be passed for
diff --git a/opendmarc/opendmarc.conf.sample b/opendmarc/opendmarc.conf.sample
index 7b31987..462e6cf 100644
--- a/opendmarc/opendmarc.conf.sample
+++ b/opendmarc/opendmarc.conf.sample
@@ -303,6 +303,15 @@
 #
 # RejectFailures false
 
+##  RejectString string
+##      default ("rejected by DMARC policy for %s")
+##
+##  This string describes the reason of reject. The message MUST contain the
+##  word "%s" (only once), which will be replaced with the RFC5322.From domain.
+##  Escaped "%" ("%%") are not allowed in this string.
+#
+# RejectString rejected by DMARC policy for %s
+
 ##  RejectMultiValueFrom { true | false }
 ##  	default "false"
 ##
diff --git a/opendmarc/opendmarc.h b/opendmarc/opendmarc.h
index e36f93a..a4593dc 100644
--- a/opendmarc/opendmarc.h
+++ b/opendmarc/opendmarc.h
@@ -34,6 +34,7 @@
 #define	BUFRSZ		2048
 #define	DEFCONFFILE	CONFIG_BASE "/opendmarc.conf"
 #define	DEFREPORTCMD	"/usr/sbin/sendmail -t -odq"
+#define DEFREJECTSTR    "rejected by DMARC policy for %s"
 #define	JOBIDUNKNOWN	"(unknown-jobid)"
 #define	MAXARGV		65536
 #define	MAXHEADER	1024