diff -ur postfix-2.4.5/src/smtpd/smtpd.c postfix-2.4.5-proxy/src/smtpd/smtpd.c
--- postfix-2.4.5/src/smtpd/smtpd.c	2007-09-11 00:27:31.181567626 +0200
+++ postfix-2.4.5-proxy/src/smtpd/smtpd.c	2007-09-11 00:26:54.177444169 +0200
@@ -2526,7 +2526,9 @@
     int     out_error;
     char  **cpp;
     const CLEANUP_STAT_DETAIL *detail;
-    const char *rfc3848_sess;
+    VSTRING *proxy_why = 0;
+    int     proxy_code;
+    const char *rfc3848_sess;
     const char *rfc3848_auth;
 
 #ifdef USE_TLS
@@ -2705,8 +2707,19 @@
 	if (state->err == CLEANUP_STAT_OK) {
 	    (void) smtpd_proxy_cmd(state, SMTPD_PROX_WANT_ANY, ".");
 	    if (state->err == CLEANUP_STAT_OK &&
-		*STR(state->proxy_buffer) != '2')
+		*STR(state->proxy_buffer) != '2') {
 		state->err = CLEANUP_STAT_CONT;
+		proxy_why = vstring_alloc(10);
+		vstring_strncpy(proxy_why, STR(state->proxy_buffer), 3);
+		if (alldig(STR(proxy_why)))
+			proxy_code = atol(STR(proxy_why));
+		else
+			proxy_code = 554;
+		vstring_strncpy(proxy_why, STR(state->proxy_buffer)+4, 5);
+		smtpd_check_reject(state, MAIL_ERROR_POLICY, proxy_code, proxy_why,
+					"%s", STR(state->proxy_buffer));
+		vstring_free(proxy_why);
+	    }
 	} else if (state->err != CLEANUP_STAT_SIZE) {
 	    state->err |= CLEANUP_STAT_PROXY;
 	    detail = cleanup_stat_detail(CLEANUP_STAT_PROXY);
diff -ur postfix-2.4.5/src/smtpd/smtpd_check.c postfix-2.4.5-proxy/src/smtpd/smtpd_check.c
--- postfix-2.4.5/src/smtpd/smtpd_check.c	2007-09-11 00:27:30.414953649 +0200
+++ postfix-2.4.5-proxy/src/smtpd/smtpd_check.c	2007-09-11 00:10:33.804822948 +0200
@@ -378,7 +378,7 @@
   * mail.
   */
 static void PRINTFLIKE(5, 6) defer_if(SMTPD_DEFER *, int, int, const char *, const char *,...);
-static int PRINTFLIKE(5, 6) smtpd_check_reject(SMTPD_STATE *, int, int, const char *, const char *,...);
+int PRINTFLIKE(5, 6) smtpd_check_reject(SMTPD_STATE *, int, int, const char *, const char *,...);
 
 #define DEFER_IF_REJECT2(state, class, code, dsn, fmt, a1, a2) \
     defer_if(&(state)->defer_if_reject, (class), (code), (dsn), (fmt), (a1), (a2))
@@ -759,7 +759,7 @@
 
 /* smtpd_check_reject - do the boring things that must be done */
 
-static int smtpd_check_reject(SMTPD_STATE *state, int error_class,
+int smtpd_check_reject(SMTPD_STATE *state, int error_class,
 			              int code, const char *dsn,
 			              const char *format,...)
 {
diff -ur postfix-2.4.5/src/smtpd/smtpd_check.h postfix-2.4.5-proxy/src/smtpd/smtpd_check.h
--- postfix-2.4.5/src/smtpd/smtpd_check.h	2007-09-11 00:27:30.414953649 +0200
+++ postfix-2.4.5-proxy/src/smtpd/smtpd_check.h	2007-09-11 00:10:33.808156052 +0200
@@ -25,6 +25,7 @@
 extern char *smtpd_check_data(SMTPD_STATE *);
 extern char *smtpd_check_eod(SMTPD_STATE *);
 extern char *smtpd_check_policy(SMTPD_STATE *, char *);
+extern int smtpd_check_reject(SMTPD_STATE *state, int error_class, int code, const char *dsn, const char *format,...);
 
 /* LICENSE
 /* .ad