diff --git a/src/vde_switch/port.c b/src/vde_switch/port.c
index 016fbf1..8c7ed75 100644
--- a/src/vde_switch/port.c
+++ b/src/vde_switch/port.c
@@ -17,6 +17,8 @@
 #include <grp.h>
 #include <pwd.h>
 #include <ctype.h>
+#include <limits.h>
+#include <stdint.h>
 
 #include <config.h>
 #include <vde.h>
@@ -41,6 +43,11 @@ static int stdqlen=128;
 
 static struct port **portv;
 
+static int external_numports(void)
+{
+	return (numports > 0) ? numports - 1 : 0;
+}
+
 #ifdef DEBUGOPT
 #define DBGPORTNEW (dl) 
 #define DBGPORTDEL (dl+1) 
@@ -730,7 +737,7 @@ void handle_in_packet(struct endpoint *ep,  struct packet *packet, int len)
 
 static int showinfo(FILE *fd)
 {
-	printoutc(fd,"Numports=%d",numports);
+	printoutc(fd,"Numports=%d",external_numports());
 	printoutc(fd,"HUB=%s",(pflag & HUB_TAG)?"true":"false");
 #ifdef PORTCOUNTERS
 	printoutc(fd,"counters=true");
@@ -745,53 +752,60 @@ static int showinfo(FILE *fd)
 
 static int portsetnumports(int val)
 {
-	if(val > 0) {
+	if (val > 0 && val <= INT_MAX - 1) {
 		/*resize structs*/
 		int i;
-		for(i=val;i<numports;i++)
+		int internal_numports = val + 1;
+		size_t internal_numports_sz = (size_t)internal_numports;
+
+		if (internal_numports_sz > SIZE_MAX / sizeof(struct port *)) {
+			printlog(LOG_ERR,"Numport resize overflow");
+			exit(1);
+		}
+		for(i=internal_numports;i<numports;i++)
 			if(portv[i] != NULL)
 				return EADDRINUSE;
-		portv=realloc(portv,val*sizeof(struct port *));
+		portv=realloc(portv,internal_numports_sz * sizeof(struct port *));
 		if (portv == NULL) {
 			printlog(LOG_ERR,"Numport resize failed portv %s",strerror(errno));
 			exit(1);
 		}
 		for (i=0;i<NUMOFVLAN;i++) { 
 			if (vlant[i].table) {
-				vlant[i].table=ba_realloc(vlant[i].table,numports,val);
+				vlant[i].table=ba_realloc(vlant[i].table,numports,internal_numports);
 				if (vlant[i].table == NULL) {
 					printlog(LOG_ERR,"Numport resize failed vlan tables vlan table %s",strerror(errno));
 					exit(1);
 				}
 			}
 			if (vlant[i].bctag) {
-				vlant[i].bctag=ba_realloc(vlant[i].bctag,numports,val);
+				vlant[i].bctag=ba_realloc(vlant[i].bctag,numports,internal_numports);
 				if (vlant[i].bctag == NULL) {
 					printlog(LOG_ERR,"Numport resize failed vlan tables vlan bctag %s",strerror(errno));
 					exit(1);
 				}
 			}
 			if (vlant[i].bcuntag) {
-				vlant[i].bcuntag=ba_realloc(vlant[i].bcuntag,numports,val);
+				vlant[i].bcuntag=ba_realloc(vlant[i].bcuntag,numports,internal_numports);
 				if (vlant[i].bcuntag == NULL) {
 					printlog(LOG_ERR,"Numport resize failed vlan tables vlan bctag %s",strerror(errno));
 					exit(1);
 				}
 			}
 			if (vlant[i].notlearning) {
-				vlant[i].notlearning=ba_realloc(vlant[i].notlearning,numports,val);
+				vlant[i].notlearning=ba_realloc(vlant[i].notlearning,numports,internal_numports);
 				if (vlant[i].notlearning == NULL) {
 					printlog(LOG_ERR,"Numport resize failed vlan tables vlan notlearning %s",strerror(errno));
 					exit(1);
 				}
 			}
 		}
-		for (i=numports;i<val;i++)
+		for (i=numports;i<internal_numports;i++)
 			portv[i]=NULL;
 #ifdef FSTP
-		fstsetnumports(val);
+		fstsetnumports(internal_numports);
 #endif
-		numports=val;
+		numports=internal_numports;
 		return 0;
 	} else 
 		return EINVAL;
diff --git a/src/vde_switch/vde_switch.c b/src/vde_switch/vde_switch.c
index 75c23a2..b74a62c 100644
--- a/src/vde_switch/vde_switch.c
+++ b/src/vde_switch/vde_switch.c
@@ -13,6 +13,7 @@
 #include <string.h>
 #include <signal.h>
 #include <syslog.h>
+#include <limits.h>
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -406,7 +407,11 @@ static int parse_globopt(int c, char *optarg)
 			}
 			break;
 		case 'n':
-			sscanf(optarg,"%i",&numports);
+			if (sscanf(optarg,"%i",&numports) != 1 ||
+					numports < 1 || numports > INT_MAX - 1) {
+				printlog(LOG_ERR,"Invalid number of ports %s",optarg);
+				Usage();
+			}
 			break;
 		case 'v':
 			version();
@@ -601,9 +606,9 @@ int main(int argc, char **argv)
 	atexit(cleanup);
 	hash_init(hash_size);
 #ifdef FSTP
-	fst_init(numports);
+	fst_init(numports + 1);
 #endif
-	port_init(numports);
+	port_init(numports + 1);
 	init_mods();
 	loadrcfile();
 	qtimer_init();