diff --git a/functions.h b/functions.h
--- a/functions.h
+++ b/functions.h
@@ -126,7 +126,7 @@ void NetworkReceive();
 void NetworkSend();
 void NetworkProcessCommands();
 void NetworkListen(int port);
-void NetworkInitialize();
+void NetworkInitialize(const char *hostname);
 void NetworkShutdown();
 void NetworkSendCommand(TileIndex tile, uint32 p1, uint32 p2, uint32 cmd, CommandCallback *callback);
 void NetworkStartSync();
diff --git a/main_gui.c b/main_gui.c
--- a/main_gui.c
+++ b/main_gui.c
@@ -597,7 +597,7 @@ static Window *PopupMainPlayerToolbMenu(
 	w = AllocateWindow(x, 0x16, 0xF1, 0x52, PlayerMenuWndProc, WC_TOOLBAR_MENU, _player_menu_widgets);
 	w->flags4 &= ~WF_WHITE_BORDER_MASK;
 	WP(w,menu_d).item_count = 0;
-	WP(w,menu_d).sel_index = _local_player != 0xff ? _local_player : 0;
+	WP(w,menu_d).sel_index = _local_player != OWNER_SPECTATOR ? _local_player : 0;
 	WP(w,menu_d).action_id = main_button;
 	WP(w,menu_d).main_button = main_button;
 	WP(w,menu_d).checked_items = gray;
@@ -1633,7 +1633,7 @@ static void MainToolbarWndProc(Window *w
 		GfxFillRect(0, 0, w->width-1, w->height-1, 0x80B4);
 
 		// if spectator, disable things
-		if (_current_player == 0xff){
+		if (_current_player == OWNER_SPECTATOR){
 			w->disabled_state |= (1 << 0) | (1 << 19) | (1<<20) | (1<<21) | (1<<22) | (1<<23);
 		} else {
 			w->disabled_state &= ~((1 << 0) | (1 << 19) | (1<<20) | (1<<21) | (1<<22) | (1<<23));
@@ -1965,7 +1965,7 @@ void StatusBarWndProc(Window *w, WindowE
 		SET_DPARAM16(0, _date);
 		DrawStringCentered(70, 1, ((_pause||_patches.status_long_date)?STR_00AF:STR_00AE), 0);
 		
-		p = _local_player == 0xff ? NULL : DEREF_PLAYER(_local_player);
+		p = _local_player == OWNER_SPECTATOR ? NULL : DEREF_PLAYER(_local_player);
 
 		if (p) {
 			// Draw player money
@@ -1996,7 +1996,7 @@ void StatusBarWndProc(Window *w, WindowE
 		if (e->click.widget == 1) {
 			ShowLastNewsMessage();
 		} else if (e->click.widget == 2) {
-			if (_local_player != 0xff) ShowPlayerFinances(_local_player);
+			if (_local_player != OWNER_SPECTATOR) ShowPlayerFinances(_local_player);
 		} else {
 			ResetObjectToPlace();
 		}
diff --git a/network.c b/network.c
--- a/network.c
+++ b/network.c
@@ -482,13 +482,13 @@ static void HandleFilePacket(FilePacketH
 			// send a command to make a new player
 			_local_player = 0;
 			NetworkSendCommand(0, 0, 0, CMD_PLAYER_CTRL, NULL);
-			_local_player = 0xff;
+			_local_player = OWNER_SPECTATOR;
 		} else {
 			// take control over an existing company
 			if (DEREF_PLAYER(_network_playas-1)->is_active)
 				_local_player = _network_playas-1;
 			else
-				_local_player = 0xff;
+				_local_player = OWNER_SPECTATOR;
 		}
 
 	} else {
@@ -971,9 +971,10 @@ void NetworkListen(int port)
 	_listensocket = ls;
 }
 
-void NetworkInitialize()
+void NetworkInitialize(const char *hostname)
 {
 	ClientState *cs;
+
 #if defined(WIN32)
 	WSADATA wsa;
 	if (WSAStartup(MAKEWORD(2,0), &wsa) != 0)
@@ -993,8 +994,15 @@ void NetworkInitialize()
 	for(cs=_clients; cs != &_clients[MAX_CLIENTS]; cs++)
 		cs->socket = INVALID_SOCKET;
 	
-	// startup udp listener
-	NetworkUDPListen(_network_port);
+	/*	startup udp listener
+	 *	- only if this instance is a server, so clients can find it
+	 *	OR
+	 *  - a client, wanting to find a server to connect to
+	 */
+	if (hostname == NULL  || strcmp(hostname,"auto") == 0) {
+		printf("Trying to open UDP port...\n");		
+		NetworkUDPListen(_network_port);
+	}
 }
 
 void NetworkShutdown()
@@ -1168,7 +1176,7 @@ bool NetworkUDPSearchServer() {
 #else // ENABLE_NETWORK
 
 // stubs
-void NetworkInitialize() {}
+void NetworkInitialize(const char *hostname) {}
 void NetworkShutdown() {}
 void NetworkListen(int port) {}
 void NetworkConnect(const char *hostname, int port) {}
diff --git a/network_gui.c b/network_gui.c
--- a/network_gui.c
+++ b/network_gui.c
@@ -26,7 +26,7 @@ void ConnectToServer(byte* b)
 {
 	_networking = true;
 	
-	NetworkInitialize();
+	NetworkInitialize(b);
 	DEBUG(misc, 1) ("Connecting to %s %d\n", b, _network_port);
 	NetworkConnect(b, _network_port);
 }
@@ -177,7 +177,7 @@ void ShowNetworkGameWindow()
 void StartServer()
 {
 	_networking = true;
-	NetworkInitialize();
+	NetworkInitialize(NULL);
 	DEBUG(misc, 1) ("Listening on port %d\n", _network_port);
 	NetworkListen(_network_port);
 	_networking_server = true;
diff --git a/players.c b/players.c
--- a/players.c
+++ b/players.c
@@ -581,7 +581,7 @@ void PlayersYearlyLoop()
 		}
 	}
 
-	if (_patches.show_finances && _local_player != 0xff) {
+	if (_patches.show_finances && _local_player != OWNER_SPECTATOR) {
 		ShowPlayerFinances(_local_player);
 		p = DEREF_PLAYER(_local_player);
 		if (p->num_valid_stat_ent > 5 && p->old_economy[0].performance_history < p->old_economy[4].performance_history) {
@@ -632,7 +632,7 @@ int32 CmdPlayerCtrl(int x, int y, uint32
 	switch(p1 & 0xff) {
 	case 0: // make new player
 		p = DoStartupNewPlayer(false);
-		if (_local_player == 0xff && p != NULL) {
+		if (_local_player == OWNER_SPECTATOR && p != NULL) {
 			_local_player = p->index;
 			MarkWholeScreenDirty();
 		}
diff --git a/screenshot.c b/screenshot.c
--- a/screenshot.c
+++ b/screenshot.c
@@ -422,7 +422,7 @@ static char *MakeScreenshotName(const ch
 	char *base;
 	int serial;
 
-	if (_game_mode == GM_EDITOR || _local_player == 0xff) {
+	if (_game_mode == GM_EDITOR || _local_player == OWNER_SPECTATOR) {
 		sprintf(_screenshot_name, "screenshot");
 	} else {
 		Player *p = &_players[_local_player];
diff --git a/town_gui.c b/town_gui.c
--- a/town_gui.c
+++ b/town_gui.c
@@ -29,7 +29,7 @@ static uint GetMaskOfTownActions(int *nu
 	uint avail_buttons = 0x7F; // by default all buttons except bribe are enabled.
 	uint buttons;
 
-	if (_local_player != 0xff) {
+	if (_local_player != OWNER_SPECTATOR) {
 		// bribe option enabled?
 		if (_patches.bribe) {
 			// if unwanted, disable everything.
diff --git a/ttd.c b/ttd.c
--- a/ttd.c
+++ b/ttd.c
@@ -489,7 +489,15 @@ int ttd_main(int argc, char* argv[])
 		case 'm': ttd_strlcpy(musicdriver, mgo.opt, sizeof(musicdriver)); break;
 		case 's': ttd_strlcpy(sounddriver, mgo.opt, sizeof(sounddriver)); break;
 		case 'v': ttd_strlcpy(videodriver, mgo.opt, sizeof(videodriver)); break;
-		case 'n': network=1; if (mgo.opt) {network_conn = mgo.opt; network++;} break;
+		case 'n': {
+				network = 1; 
+				if ((bool)mgo.opt) {
+					network_conn = mgo.opt; 
+					network++;
+				}
+				else
+					network_conn = NULL;
+			} break;
 		case 'r': ParseResolution(resolution, mgo.opt); break;
 		case 'l': {
 				language = mgo.opt;
@@ -518,7 +526,7 @@ int ttd_main(int argc, char* argv[])
 			break;
 		case 'p': {
 			int i = atoi(mgo.opt);
-			if (IS_INT_INSIDE(i, 0, 8))	_network_playas = i + 1;
+			if (IS_INT_INSIDE(i, 0, MAX_PLAYERS))	_network_playas = i + 1;
 			break;
 		}
 		case -2:
@@ -573,7 +581,7 @@ int ttd_main(int argc, char* argv[])
 	if (network) {
 		_networking = true;
 		
-		NetworkInitialize();
+		NetworkInitialize(network_conn);
 		if (network==1) {
 			DEBUG(misc, 1) ("Listening on port %d\n", _network_port);
 			NetworkListen(_network_port);
@@ -875,7 +883,7 @@ static void DoAutosave()
 {
 	char buf[200];
 	
-	if (_patches.keep_all_autosave && _local_player != 255) {
+	if (_patches.keep_all_autosave && _local_player != OWNER_SPECTATOR) {
 		Player *p;
 		char *s;
 		sprintf(buf, "%s%s", _path.autosave_dir, PATHSEP);
diff --git a/ttd.h b/ttd.h
--- a/ttd.h
+++ b/ttd.h
@@ -469,9 +469,10 @@ enum Sprites {
 };
 
 enum MAP_OWNERS {
-	OWNER_TOWN = 0xf, // a town owns the tile
-	OWNER_NONE = 0x10,// nobody owns the tile
-	OWNER_WATER= 0x11,// "water" owns the tile
+	OWNER_TOWN			= 0xf, // a town owns the tile
+	OWNER_NONE			= 0x10,// nobody owns the tile
+	OWNER_WATER			= 0x11,// "water" owns the tile
+	OWNER_SPECTATOR	= 0xff, // spectator in MP or in scenario editor
 };
 
 VARDEF bool _savegame_sort_dirty;