+#ifdef EXPERIMENTAL_DMARC
+uschar * s, * s2;
+
+/* For DMARC if there is a specific sender set, expand the variable for the
+header From: and grab the address from that for the envelope FROM. */
+
+if ( ident == ERRMESS_DMARC_FORENSIC
+ && dmarc_forensic_sender
+ && (s = expand_string(dmarc_forensic_sender))
+ && *s
+ && (s2 = expand_string(string_sprintf("${address:%s}", s)))
+ && *s2
+ )
+ pid = child_open_exim2(&fd, s2, bounce_sender_authentication);
+else
+ {
+ s = NULL;
+ pid = child_open_exim(&fd);
+ }
+
+#else
+pid = child_open_exim(&fd);
+#endif