diff -Nru postfix-2.8.1.org/src/global/mail_params.h postfix-2.8.1.mod/src/global/mail_params.h
--- postfix-2.8.1.org/src/global/mail_params.h	2011-01-17 15:56:39.000000000 +0100
+++ postfix-2.8.1.mod/src/global/mail_params.h	2011-03-16 03:10:14.262913306 +0100
@@ -1123,6 +1123,12 @@
 #define DEF_LMTP_GENERIC_MAPS	""
 extern char *var_smtp_generic_maps;
 
+#define VAR_SMTP_SENDER_MAPS	"smtp_sender_maps"
+#define DEF_SMTP_SENDER_MAPS	""
+#define VAR_LMTP_SENDER_MAPS	"lmtp_sender_maps"
+#define DEF_LMTP_SENDER_MAPS	""
+extern char *var_smtp_sender_maps;
+
  /*
   * SMTP server. The soft error limit determines how many errors an SMTP
   * client may make before we start to slow down; the hard error limit
diff -Nru postfix-2.8.1.org/src/smtp/smtp.c postfix-2.8.1.mod/src/smtp/smtp.c
--- postfix-2.8.1.org/src/smtp/smtp.c	2010-12-31 02:19:44.000000000 +0100
+++ postfix-2.8.1.mod/src/smtp/smtp.c	2011-03-16 03:13:01.775917207 +0100
@@ -800,6 +800,7 @@
 #endif
 
 char   *var_smtp_generic_maps;
+char   *var_smtp_sender_maps;
 char   *var_prop_extension;
 bool    var_smtp_sender_auth;
 char   *var_lmtp_tcp_port;
@@ -829,6 +830,7 @@
 SCACHE *smtp_scache;
 MAPS   *smtp_ehlo_dis_maps;
 MAPS   *smtp_generic_maps;
+MAPS   *smtp_sender_maps;
 int     smtp_ext_prop_mask;
 unsigned smtp_dns_res_opt;
 MAPS   *smtp_pix_bug_maps;
@@ -1096,6 +1098,14 @@
 			DICT_FLAG_LOCK | DICT_FLAG_FOLD_FIX);
 
     /*
+     * Sender maps
+     */
+    if (*var_smtp_sender_maps)
+        smtp_sender_maps =
+             maps_create(VAR_SMTP_SENDER_MAPS, var_smtp_sender_maps,
+                         DICT_FLAG_LOCK | DICT_FLAG_FOLD_FIX);
+    
+    /*
      * Header/body checks.
      */
     smtp_header_checks = hbc_header_checks_create(
diff -Nru postfix-2.8.1.org/src/smtp/smtp.h postfix-2.8.1.mod/src/smtp/smtp.h
--- postfix-2.8.1.org/src/smtp/smtp.h	2010-08-28 02:03:15.000000000 +0200
+++ postfix-2.8.1.mod/src/smtp/smtp.h	2011-03-16 03:10:14.365928422 +0100
@@ -178,6 +178,7 @@
 extern MAPS *smtp_pix_bug_maps;		/* PIX workarounds */
 
 extern MAPS *smtp_generic_maps;		/* make internal address valid */
+extern MAPS *smtp_sender_maps;
 extern int smtp_ext_prop_mask;		/* address externsion propagation */
 extern unsigned smtp_dns_res_opt;	/* DNS query flags */
 
diff -Nru postfix-2.8.1.org/src/smtp/smtp_params.c postfix-2.8.1.mod/src/smtp/smtp_params.c
--- postfix-2.8.1.org/src/smtp/smtp_params.c	2010-08-28 02:03:15.000000000 +0200
+++ postfix-2.8.1.mod/src/smtp/smtp_params.c	2011-03-16 03:10:14.397841397 +0100
@@ -43,6 +43,7 @@
 	VAR_SMTP_TLS_POLICY, DEF_SMTP_TLS_POLICY, &var_smtp_tls_policy, 0, 0,
 	VAR_PROP_EXTENSION, DEF_PROP_EXTENSION, &var_prop_extension, 0, 0,
 	VAR_SMTP_GENERIC_MAPS, DEF_SMTP_GENERIC_MAPS, &var_smtp_generic_maps, 0, 0,
+	VAR_SMTP_SENDER_MAPS, DEF_SMTP_SENDER_MAPS, &var_smtp_sender_maps, 0, 0,
 	VAR_LMTP_TCP_PORT, DEF_LMTP_TCP_PORT, &var_lmtp_tcp_port, 0, 0,
 	VAR_SMTP_PIX_BUG_WORDS, DEF_SMTP_PIX_BUG_WORDS, &var_smtp_pix_bug_words, 0, 0,
 	VAR_SMTP_PIX_BUG_MAPS, DEF_SMTP_PIX_BUG_MAPS, &var_smtp_pix_bug_maps, 0, 0,
diff -Nru postfix-2.8.1.org/src/smtp/smtp_proto.c postfix-2.8.1.mod/src/smtp/smtp_proto.c
--- postfix-2.8.1.org/src/smtp/smtp_proto.c	2011-01-08 01:12:06.000000000 +0100
+++ postfix-2.8.1.mod/src/smtp/smtp_proto.c	2011-03-16 03:10:14.422930785 +0100
@@ -1132,10 +1132,10 @@
     /*
      * Macros for readability.
      */
-#define REWRITE_ADDRESS(dst, src) do { \
+#define REWRITE_ADDRESS(dst, src, map) do { \
 	vstring_strcpy(dst, src); \
-	if (*(src) && smtp_generic_maps) \
-	    smtp_map11_internal(dst, smtp_generic_maps, \
+	if (*(src) && map) \
+	    smtp_map11_internal(dst, map, \
 		smtp_ext_prop_mask & EXT_PROP_GENERIC); \
     } while (0)
 
@@ -1321,7 +1321,10 @@
 	case SMTP_STATE_MAIL:
 	    request->msg_stats.reuse_count = session->reuse_count;
 	    GETTIMEOFDAY(&request->msg_stats.conn_setup_done);
-	    REWRITE_ADDRESS(session->scratch2, request->sender);
+	    if (smtp_sender_maps)
+	    	REWRITE_ADDRESS(session->scratch2, request->sender, smtp_sender_maps);
+	    else
+	    	REWRITE_ADDRESS(session->scratch2, request->sender, smtp_generic_maps);
 	    QUOTE_ADDRESS(session->scratch, vstring_str(session->scratch2));
 	    vstring_sprintf(next_command, "MAIL FROM:<%s>",
 			    vstring_str(session->scratch));
@@ -1396,7 +1399,7 @@
 	     */
 	case SMTP_STATE_RCPT:
 	    rcpt = request->rcpt_list.info + send_rcpt;
-	    REWRITE_ADDRESS(session->scratch2, rcpt->address);
+	    REWRITE_ADDRESS(session->scratch2, rcpt->address, smtp_generic_maps);
 	    QUOTE_ADDRESS(session->scratch, vstring_str(session->scratch2));
 	    vstring_sprintf(next_command, "RCPT TO:<%s>",
 			    vstring_str(session->scratch));