diff --git a/client b/client
index 7d4df29..c2d7765 100755
Binary files a/client and b/client differ
diff --git a/client.c b/client.c
index e110ecc..48ced06 100644
--- a/client.c
+++ b/client.c
@@ -4,23 +4,56 @@
 
 int main(int argc, char* argv[]){
 
-	/* [1] Initialisation
+	/* [1] Initialization + arguments
 	=========================================================*/
 	/* (1) Socket information */
 	struct sockaddr_in server_addr; // server info
 	int sock; // socket
+	int port; // chosen port
+	char hostname[24]; // chosen hostname
 	
 	/* (2) Misc. information */
 	int bytes; // transfer count
 	char* to_send = (char*) malloc( BUFSIZE * sizeof(char) );
 	char* to_recv = (char*) malloc( BUFSIZE * sizeof(char) );
 
-	
 
-
-	/* [2] Create UPD socket and get target data
+	/* [2] Manage arguments
 	=========================================================*/
-	sock = xconnect("localhost", 4000, &server_addr);
+	/* (1) Manage arguments count */
+	if( argc < 3 ){
+		printf("Missing arguments\nUsage: client hostname port [message]\n");
+		return 1;
+	}
+
+	/* (2) Manage @hostname argument */
+	if( strlen(argv[1]) > 24 || sscanf(argv[1], "%s", hostname) <= 0 ){
+		printf("argument error: hostname must be a string (max: 24 characters long)\n");
+		return 1;
+	}
+
+	/* (3) Manage port argument */
+	if( sscanf(argv[2], "%d", &port) <= 0 ){
+		printf("argument error: port must be a valid integer\n");
+		return 1;
+	}
+
+	/* (4) Manage optional @message argument */
+	if( argc >= 4 ){
+
+		if( strlen(argv[3]) > BUFSIZE || sscanf(argv[3], "%s", to_send) <= 0 ){
+			printf("argument error: message must be a string (max: %d characters long)\n", BUFSIZE);
+			return 1;
+		}
+
+	}else
+		strcpy(to_send, "client default message");
+	
+		
+
+	/* [3] Create UPD socket and get target data
+	=========================================================*/
+	sock = xconnect(hostname, port, &server_addr);
 
 	/* (1-) Manage error */
 	if( sock == -1 ){
@@ -29,15 +62,12 @@ int main(int argc, char* argv[]){
 	}
 
 
-	/* [3] Send message
+	/* [4] Send message
 	=========================================================*/
-	/* (1) Set message to send */
-	strcpy(to_send, "client message");
-
-	/* (2) Send message to server */
+	/* (1) Send message to server */
 	bytes = xsend(sock, to_send, &server_addr);
 
-	/* (3) Check if send succesfully */
+	/* (2) Check if send succesfully */
 	if( bytes == -1 ){
 		perror("erreur envoi message");
 		exit(1);
@@ -47,7 +77,7 @@ int main(int argc, char* argv[]){
 
 
 
-	/* [4] Wait for response
+	/* [5] Wait for response
 	=========================================================*/
 	/* (1) Wait for response */
 	bytes = xlisten(sock, &server_addr, to_recv, BUFSIZE);
@@ -62,7 +92,7 @@ int main(int argc, char* argv[]){
 	printf("*** received : '%s'\n", to_recv);
 
 
-	/* [5] Close socket
+	/* [6] Close socket
 	=========================================================*/
 	close(sock);
 
diff --git a/client.o b/client.o
index d109e27..8cae374 100644
Binary files a/client.o and b/client.o differ
diff --git a/server b/server
index f6d3c26..7c26bea 100755
Binary files a/server and b/server differ
diff --git a/server.c b/server.c
index 916f900..f40639f 100644
--- a/server.c
+++ b/server.c
@@ -10,6 +10,7 @@ int main(int argc, char* argv[]){
 	// Client
 	struct sockaddr_in addr_client;
 	char client_ip[20];
+	int port; // chosen port
 	// Socket
 	int sock;
 
@@ -20,11 +21,40 @@ int main(int argc, char* argv[]){
 	int bytes; // transfer count
 
 
+	/* [2] Manage arguments
+	=========================================================*/
+	/* (1) Manage arguments count */
+	if( argc < 2 ){
+		printf("Missing arguments\nUsage: server port [message]\n");
+		printf("port = 0 : automatic port\n");
+		return 1;
+	}
 
-	/* [2] Create socket
+	/* (2) Manage port argument */
+	if( sscanf(argv[1], "%d", &port) <= 0 ){
+		printf("argument error: port must be a valid integer\n");
+		printf("port = 0 : automatic port\n");
+		return 1;
+	}
+
+	/* (3) Manage optional @message argument */
+	if( argc >= 3 ){
+
+		if( strlen(argv[2]) > BUFSIZE || sscanf(argv[2], "%s", to_send) <= 0 ){
+			printf("argument error: message must be a string (max: %d characters long)\n", BUFSIZE);
+			return 1;
+		}
+
+	}else
+		strcpy(to_send, "server default message");
+
+
+
+
+	/* [3] Create socket
 	=========================================================*/
 	/* (1) Create socket */
-	sock = xbind(4000);
+	sock = xbind(port);
 
 	/* (1-) Manage error */
 	if( sock == -1 ){
@@ -33,7 +63,7 @@ int main(int argc, char* argv[]){
 	}
 
 
-	/* [3] Wait for client message
+	/* [4] Wait for client message
 	=========================================================*/
 	/* (1) Listen to data */
 	bytes = xlisten(sock, &addr_client, to_recv, BUFSIZE);
@@ -50,21 +80,21 @@ int main(int argc, char* argv[]){
 
 	printf("*** received '%s' (%d bytes) from %s:%d\n", to_recv, bytes, client_ip, ntohs(addr_client.sin_port));
 
-	/* [4] Send response
+	/* [5] Send response
 	=========================================================*/
-	/* (1) Set response data */
-	strcpy(to_send, "server response");
-	
-	/* (2) Send response */
+	/* (1) Send response */
 	bytes = xsend(sock, to_send, &addr_client);
 
-	/* (3) Manage error */
+	/* (2) Manage error */
 	if( bytes == -1 ){
 		perror("erreur envoi réponse");
 		exit(1);
 	}
 
-	/* [5] Close socket
+
+	/* [6] Close socket
 	=========================================================*/
 	close(sock);
+
+	return 0;
 }
diff --git a/server.o b/server.o
index dfff7f1..4e516f9 100644
Binary files a/server.o and b/server.o differ