diff --git a/tools/tools/mctest/mctest.1 b/tools/tools/mctest/mctest.1
index 17729f2e8748..3ca57eee013e 100644
--- a/tools/tools/mctest/mctest.1
+++ b/tools/tools/mctest/mctest.1
@@ -33,6 +33,8 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl i Ar interface
+.Op Fl g Ar group
+.Op Fl b Ar base port
 .Op Fl n Ar number
 .Op Fl s Ar size
 .Op Fl t Ar inter-packet gap
@@ -57,6 +59,10 @@ The options are as follows:
 .Bl -tag -width ".Fl d Ar argument"
 .It Fl i Ar interface
 Network interface, which can be found with ifconfig(1).
+.It Fl i Ar group
+Multicast group
+.It Fl i Ar base port
+Port on which to listen
 .It Fl s Ar size
 Packet size in bytes.
 .It Fl n Ar number
diff --git a/tools/tools/mctest/mctest.cc b/tools/tools/mctest/mctest.cc
index 436efcefd2ea..7140b62cd723 100644
--- a/tools/tools/mctest/mctest.cc
+++ b/tools/tools/mctest/mctest.cc
@@ -92,7 +92,7 @@ void usage(string message)
 // @return 0 for 0K, -1 for error, sets errno
 //
 int sink(char *interface, struct in_addr *group, int pkt_size, int number,
-	 int clients, int client) {
+	 int clients, int client, short base_port) {
 
     
     int sock, backchan;
@@ -181,7 +181,7 @@ int sink(char *interface, struct in_addr *group, int pkt_size, int number,
 	 * the sender. 
 	 */
 	if (n % clients == client) {
-		recvd.sin_port = htons(SERVER_PORT + client);
+		recvd.sin_port = htons(base_port + client);
 		if (sendto(backchan, packet, pkt_size, 0, 
 			   (struct sockaddr *)&recvd, sizeof(recvd)) < 0) {
 		    perror("sendto failed");
@@ -249,7 +249,7 @@ void* server(void *passed) {
     bzero(&addr, sizeof(addr));
     addr.sin_family = AF_INET;
     addr.sin_addr.s_addr = INADDR_ANY;
-    addr.sin_port = htons(SERVER_PORT + args->client);
+    addr.sin_port = htons(args->client);
     addr.sin_len = sizeof(addr);
 
     if (bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
@@ -295,7 +295,7 @@ void* server(void *passed) {
 // @return 0 for OK, -1 for error, sets errno
 //
 int source(char *interface, struct in_addr *group, int pkt_size, 
-	   int number, int gap, int clients) {
+	   int number, int gap, int clients, short base_port) {
 
     int sock;
     struct sockaddr_in addr;
@@ -367,7 +367,7 @@ int source(char *interface, struct in_addr *group, int pkt_size,
         args[i].pkt_size = pkt_size;
         args[i].packets = received[i];
         args[i].number = number / clients;
-	args[i].client = i;
+	args[i].client = base_port + i;
 	if (pthread_create(&thread[i], NULL, server, &args[i]) < 0) {
 	    perror("failed to create server thread");
 	    return -1;
@@ -440,11 +440,12 @@ int main(int argc, char**argv)
 	bool server = false;	///< are we on he receiving end of multicast
 	int client = 0;		///< for receivers which client are we
 	int clients = 1;	///< for senders how many clients are there
+	short base_port = SERVER_PORT; ///< to have multiple copies running at once
 	
-	if (argc < 2 || argc > 14)
+	if (argc < 2 || argc > 16)
 		usage();
 	
-	while ((ch = getopt(argc, argv, "M:m:g:i:n:s:t:rh")) != -1) {
+	while ((ch = getopt(argc, argv, "M:m:g:i:n:s:t:b:rh")) != -1) {
 		switch (ch) {
 		case 'g':
 			group = new (struct in_addr );
@@ -482,6 +483,9 @@ int main(int argc, char**argv)
 		case 'M':
 			clients = atoi(optarg);
 			break;
+		case 'b':
+			base_port = atoi(optarg);
+			break;
 		case 'h':
 			usage(string("Help\n"));
 			break;
@@ -491,11 +495,13 @@ int main(int argc, char**argv)
 	if (server) {
 	    if (clients <= 0 || client < 0)
 		usage("must specify client (-m) and number of clients (-M)");
-	    sink(interface, group, pkt_size, number, clients, client);
+	    sink(interface, group, pkt_size, number, clients, client,
+		 base_port);
 	} else {
 	    if (clients <= 0)
 		usage("must specify number of clients (-M)");
-	    source(interface, group, pkt_size, number, gap, clients);
+	    source(interface, group, pkt_size, number, gap, clients, 
+		   base_port);
 	}
 	
 }
diff --git a/tools/tools/mctest/mctest_run.sh b/tools/tools/mctest/mctest_run.sh
index ec41d3767edf..2e4ac02fe7d8 100644
--- a/tools/tools/mctest/mctest_run.sh
+++ b/tools/tools/mctest/mctest_run.sh
@@ -7,6 +7,7 @@
 # Defaults
 size=1024
 number=100
+base=""
 group=""
 interface="cxgb0"
 remote="ssh"
@@ -15,7 +16,7 @@ gap=1000
 
 # Arguments are s (size), g (group), n (number), and c (command) followed
 # by a set of hostnames.
-args=`getopt s:g:n:c:i: $*`
+args=`getopt s:g:n:c:i:b: $*`
 if [ $? != 0 ]
 then
     echo 'Usage: mctest_run -s size -g group -n number -c remote command host1 host2 hostN'
@@ -42,6 +43,9 @@ do
       -i)
 	  interface=$3;
 	  shift 2;;
+      -b) 
+	  base=$3;
+	  shift 2;;
       --)
 	  shift; break;;
       esac
@@ -56,7 +60,7 @@ now=`date "+%Y%m%d%H%M"`
 for host in $*
 do
   output=$host\_$interface\_$size\_$number\.$now
-  $remote $host $command -r -M $# -m $current -n $number -s $size -i $interface > $output &
+  $remote $host $command -r -M $# -b $base -g $group -m $current -n $number -s $size -i $interface > $output &
   sleep 1
   current=`expr $current + 1 `;
 done
@@ -64,4 +68,4 @@ done
 #
 # Start the source/collector on this machine
 #
-$command -M $# -n $number -s $size -i le1 -t $gap > `uname -n`\_$size\_$number\.$now
+$command -M $# -b $base -g $group -n $number -s $size -i $interface -t $gap > `uname -n`\_$size\_$number\.$now