diff --git a/doc/rdesktop.1 b/doc/rdesktop.1
index c48fc0c..30042f8 100644
--- a/doc/rdesktop.1
+++ b/doc/rdesktop.1
@@ -92,6 +92,11 @@ size, in pixels. The special word "standard" means 18 pixels.
 .BR "-T <title>"
 Sets the window title.
 .TP
+.BR "-N"
+Enable numlock syncronization between the Xserver and the remote RDP
+session.  This is useful with applications that looks at the numlock
+state, but might cause problems with some Xservers like Xvnc. 
+.TP
 .BR "-a <bpp>"
 Sets the colour depth for the connection (8, 15, 16 or 24).
 More than 8 bpp are only supported when connecting to Windows XP
diff --git a/keymaps/common b/keymaps/common
index f773de6..f53c885 100644
--- a/keymaps/common
+++ b/keymaps/common
@@ -116,38 +116,38 @@ KP_Subtract 0x4a
 KP_Add 0x4e
 KP_Enter 0x9c
 
-KP_Decimal 0x53
-KP_Separator 0x53
+KP_Decimal 0x53 numlock
+KP_Separator 0x53 numlock
 KP_Delete 0x53
 
-KP_0 0x52 
+KP_0 0x52 numlock
 KP_Insert 0x52
 
-KP_1 0x4f 
+KP_1 0x4f numlock
 KP_End 0x4f
 
-KP_2 0x50 
+KP_2 0x50 numlock
 KP_Down 0x50
 
-KP_3 0x51 
+KP_3 0x51 numlock
 KP_Next 0x51
 
-KP_4 0x4b 
+KP_4 0x4b numlock
 KP_Left 0x4b
 
-KP_5 0x4c 
+KP_5 0x4c numlock
 KP_Begin 0x4c
 
-KP_6 0x4d 
+KP_6 0x4d numlock
 KP_Right 0x4d
 
-KP_7 0x47 
+KP_7 0x47 numlock
 KP_Home 0x47
 
-KP_8 0x48 
+KP_8 0x48 numlock
 KP_Up 0x48
 
-KP_9 0x49 
+KP_9 0x49 numlock
 KP_Prior 0x49
 
 #
diff --git a/keymaps/pt-br b/keymaps/pt-br
index 46a96ce..54bafc5 100644
--- a/keymaps/pt-br
+++ b/keymaps/pt-br
@@ -60,7 +60,7 @@ period 0x34
 greater 0x34 shift
 semicolon 0x35
 colon 0x35 shift
-comma 0x53
+comma 0x53 numlock
 backslash 0x56
 bar 0x56 shift
 slash 0x73
diff --git a/rdesktop.c b/rdesktop.c
index 6ad5905..1463885 100644
--- a/rdesktop.c
+++ b/rdesktop.c
@@ -66,6 +66,7 @@ BOOL g_grab_keyboard = True;
 BOOL g_hide_decorations = False;
 BOOL g_use_rdp5 = True;
 BOOL g_console_session = False;
+BOOL g_numlock_sync = False;
 extern BOOL g_owncolmap;
 
 #ifdef WITH_RDPSND
@@ -110,6 +111,7 @@ usage(char *program)
 	fprintf(stderr, "   -K: keep window manager key bindings\n");
 	fprintf(stderr, "   -S: caption button size (single application mode)\n");
 	fprintf(stderr, "   -T: window title\n");
+	fprintf(stderr, "   -N: enable numlock syncronization\n");
 	fprintf(stderr, "   -a: connection colour depth\n");
 	fprintf(stderr, "   -r: enable specified device redirection (currently: sound)\n");
 	fprintf(stderr, "   -0: attach to console\n");
@@ -229,7 +231,7 @@ main(int argc, char *argv[])
 #define VNCOPT
 #endif
 
-	while ((c = getopt(argc, argv, VNCOPT "u:d:s:c:p:n:k:g:fbeEmCDKS:T:a:r:045h?")) != -1)
+	while ((c = getopt(argc, argv, VNCOPT "u:d:s:c:p:n:k:g:fbeEmCDKS:T:Na:r:045h?")) != -1)
 	{
 		switch (c)
 		{
@@ -368,6 +370,10 @@ main(int argc, char *argv[])
 				STRNCPY(g_title, optarg, sizeof(g_title));
 				break;
 
+			case 'N':
+				g_numlock_sync = True;
+				break;
+
 			case 'a':
 				g_server_bpp = strtol(optarg, NULL, 10);
 				if (g_server_bpp != 8 && g_server_bpp != 16 && g_server_bpp != 15
diff --git a/xkeymap.c b/xkeymap.c
index ba25e22..c5be513 100644
--- a/xkeymap.c
+++ b/xkeymap.c
@@ -44,6 +44,7 @@ extern int keylayout;
 extern int g_win_button_size;
 extern BOOL g_enable_compose;
 extern BOOL g_use_rdp5;
+extern BOOL g_numlock_sync;
 
 static BOOL keymap_loaded;
 static key_translation keymap[KEYMAP_SIZE];
@@ -186,6 +187,11 @@ xkeymap_read(char *mapname)
 			MASK_ADD_BITS(modifiers, MapLeftShiftMask);
 		}
 
+		if (strstr(line_rest, "numlock"))
+		{
+			MASK_ADD_BITS(modifiers, MapNumLockMask);
+		}
+
 		if (strstr(line_rest, "localstate"))
 		{
 			MASK_ADD_BITS(modifiers, MapLocalStateMask);
@@ -361,6 +367,12 @@ handle_special_keys(uint32 keysym, unsigned int state, uint32 ev_time, BOOL pres
 			if (g_win_button_size
 			    && (get_key_state(state, XK_Alt_L) || get_key_state(state, XK_Alt_R)))
 				return True;
+		case XK_Num_Lock:
+			/* FIXME: We might want to do RDP_INPUT_SYNCHRONIZE here, if g_numlock_sync */
+			if (!g_numlock_sync)
+				/* Inhibit */
+				return True;
+
 
 	}
 	return False;
@@ -507,6 +519,33 @@ ensure_remote_modifiers(uint32 ev_time, key_translation tr)
 	if (is_modifier(tr.scancode))
 		return;
 
+	if (!g_numlock_sync)
+	{
+		/* NumLock */
+		if (MASK_HAS_BITS(tr.modifiers, MapNumLockMask)
+		    != MASK_HAS_BITS(remote_modifier_state, MapNumLockMask))
+		{
+			/* The remote modifier state is not correct */
+			uint16 new_remote_state;
+
+			if (MASK_HAS_BITS(tr.modifiers, MapNumLockMask))
+			{
+				DEBUG_KBD(("Remote NumLock state is incorrect, activating NumLock.\n"));
+				new_remote_state = KBD_FLAG_NUMLOCK;
+				remote_modifier_state = MapNumLockMask;
+			}
+			else
+			{
+				DEBUG_KBD(("Remote NumLock state is incorrect, deactivating NumLock.\n"));
+				new_remote_state = 0;
+				remote_modifier_state = 0;
+			}
+
+			rdp_send_input(0, RDP_INPUT_SYNCHRONIZE, 0, new_remote_state, 0);
+		}
+	}
+
+
 	/* Shift. Left shift and right shift are treated as equal; either is fine. */
 	if (MASK_HAS_BITS(tr.modifiers, MapShiftMask)
 	    != MASK_HAS_BITS(remote_modifier_state, MapShiftMask))
@@ -613,7 +652,8 @@ reset_modifier_keys()
 
 	reset_winkey(ev_time);
 
-	rdp_send_input(ev_time, RDP_INPUT_SYNCHRONIZE, 0, ui_get_numlock_state(state), 0);
+	if (g_numlock_sync)
+		rdp_send_input(ev_time, RDP_INPUT_SYNCHRONIZE, 0, ui_get_numlock_state(state), 0);
 }
 
 
@@ -652,6 +692,18 @@ update_modifier_state(uint8 scancode, BOOL pressed)
 		case SCANCODE_CHAR_RWIN:
 			MASK_CHANGE_BIT(remote_modifier_state, MapRightWinMask, pressed);
 			break;
+		case SCANCODE_CHAR_NUMLOCK:
+			/* KeyReleases for NumLocks are sent immediately. Toggle the
+			   modifier state only on Keypress */
+			if (pressed && !g_numlock_sync)
+			{
+				BOOL newNumLockState;
+				newNumLockState =
+					(MASK_HAS_BITS
+					 (remote_modifier_state, MapNumLockMask) == False);
+				MASK_CHANGE_BIT(remote_modifier_state,
+						MapNumLockMask, newNumLockState);
+			}
 	}
 
 #ifdef WITH_DEBUG_KBD