socket programming

[saee]

hello group,
i'm trying udp socket program. my code works fine with local host ip. i.e 127.0.0.1
according to my knowledge, if i change the ip address n give remote host's ip, two machines should communicate. it doesn't work. after runing server i checked port engaged with netstat. it shows perticular port in use.
please tell is there an other settings that i should look for?
thenk you.

[saee]

i couldn't find a solution for it yet. i have searched on net also. does anybody have a idea where shall i search for the solution at least?
thnks

[Andr3w]

Please can you post your code so we can see what's the problem and help you if possible?

Thanks!

[saee]

yes sure andr3w. here is my code.

///////////
client.cpp
////////////////////

#include <iostream>
#include <winsock2.h> 

using namespace std;
#define SERVER_PORT 3000
#define BUF_SIZE 4096 // block transfer size  
#define QUEUE_SIZE 20
#define IPAddress "127.0.0.1" // Local to the system - Loop back address

//#define IPAddress "192.168.1.11"


int main()
{
	WORD			wVersionRequested;
	WSADATA			wsaData;
	SOCKADDR_IN		server;				 //Socket address information
	SOCKET			s;
	int				err;
	int				bytesSent;
	char			buf[100] = "hi hello";
	int				addr_len = sizeof(struct sockaddr);
	
	
		
//--- INITIALIZATION -----------------------------------
	wVersionRequested = MAKEWORD( 1, 1 );
	err = WSAStartup( wVersionRequested, &wsaData );

	if ( err != 0 ) {
		printf("WSAStartup error %ld", WSAGetLastError());
		WSACleanup();
		return false;
	}
//---------------------------------------------------------

		
//---- creat a server struct.--------  
	server.sin_family = AF_INET; // address family Internet
	server.sin_port = htons (SERVER_PORT); //Port to connect on
	server.sin_addr.s_addr = inet_addr (IPAddress); //Target IP

//--------------------------------------------------------

	while(1) {
// ---- create SOCKET--------------------------------------
	s = socket (AF_INET, SOCK_DGRAM, 0); //Create socket
	if (s == INVALID_SOCKET)
	{
		printf("socket error %ld" , WSAGetLastError() );
		getchar();
		WSACleanup();
		return false; //Couldn't create the socket
	}  
//---------------------------------------------------------


//---- SEND bytes -------------------------------------------
		
		printf("trans buf:('q' to quit)\n");
		gets_s(buf);
		if ((strcmp(buf , "q") == 0) || strcmp(buf , "Q") == 0)
			break;
		bytesSent = sendto (s, buf, QUEUE_SIZE, 0, (struct sockaddr*) &server, sizeof(sockaddr));
		if(bytesSent < 0 ){
			printf("sendto fails with : %ld\n ", WSAGetLastError());
	
			WSACleanup();
		}
		else 
			printf("bytes sent :  %d\n" ,bytesSent );
//-------------------------------------------------------------------------

	}
	return 0;
}

////////////////////////
server.cpp
////////////////////////

#include <iostream>
#include <winsock2.h> 

#define SERVER_PORT 3000
//#define BUF_SIZE 4096  // block transfer size  
#define QUEUE_SIZE 20 
#define IPAddress "127.0.0.1" // Local to the system - Loop back address

//#define IPAddress "127.0.0.85"


int main()
{
	WORD		wVersionRequested;
	WSADATA		wsaData;
	SOCKET		s; 
	struct		sockaddr_in server, client;  // holds IP address 
	char		recvbuf[10] = {}; 
	int			b, opt; 
	int			err;
	int			bytesRecv;//, bytesSent;
	int			addr_len = sizeof(struct sockaddr);
	char		*val = new char;

	
//--- INITIALIZATION -----------------------------------
	wVersionRequested = MAKEWORD( 1, 1 );
	err = WSAStartup( wVersionRequested, &wsaData );

	if ( err != 0 ) {
		printf("WSAStartup error %ld", WSAGetLastError());
		WSACleanup();
		return false;
	}
//---------------------------------------------------------

//------------ server socket ----------------------------
	server.sin_addr.s_addr = inet_addr(IPAddress);//htonl(INADDR_ANY);
	server.sin_family = AF_INET; // address family Internet
	server.sin_port = htons (SERVER_PORT); //Port to connect on
//-----------------------------------------------------------------


// ---- create SOCKET--------------------------------------
	s = socket(AF_INET, SOCK_DGRAM, 0);    //0 specifies to use appropriate protocol according to request
	if (s < 0) {
		printf("socket error %ld",WSAGetLastError() );
		WSACleanup();
		return false;
	}
//--------------------------------------------------------

	
//---- BIND socket ----------------------------------------
	b = bind(s, (struct sockaddr *) &server, sizeof(sockaddr)); 
	if (b == -1) {
		printf("socket bind error %ld",WSAGetLastError() );
		WSACleanup();
		getchar();
		return false;
	}

//----------------------------------------------------------
while (1) {
		printf("\nwaiting for a connection\n");	

	
//-----------receive bytes -------------------------------------------------------------
		
		bytesRecv  = recvfrom(s, recvbuf, QUEUE_SIZE, 0, (struct sockaddr *)&client, &addr_len );
		
		if(bytesRecv < 0){
			printf("\nbytesRecv : %d\n", bytesRecv);
			printf("\nrecvfrom error : %ld\n", WSAGetLastError());
			WSACleanup();
		}
		
		printf("connection ");
		if ( bytesRecv == 0 || bytesRecv == WSAECONNRESET ) {
			printf( "Closed.\n");
			WSACleanup();
		}
		else printf("accepted\n");
		printf("received from: %s \t port : %d\n ", inet_ntoa(client.sin_addr), ntohs(client.sin_port));

		printf( " Bytes Recv: %s \n ", recvbuf );
		
//-----------------------------------------------------------------------------------------------
 
	
	}
	
	WSACleanup();
	return 0;
}

see, here in this code if i replace loopback address with other machines ip address it should work. i mean that is what i cud know till now. please tell me if there are also other settings i should check like firewalls. actually i have kept firewall off.
thank you again.

[saee]

same prob with tcp

i eve tried tcp client- server. same problem! :(
works with loop back address n not with network addresses.

[shreeram]

socket programming

hi..
your LAN activated Firewall means it generate TimedOut exception
so u check firewall settings tick On recommend radio button

[saee]

hi shreeram,
i tried. no luck. :(
r u sure the code is correct?

[saee]

help!

can anybody please answer me?

[saee]

ok. let me state my problem newly.
my client n server can send n receive data from labview's udp port. but not to each other.as, it can communicate with labview, the code is correct. but i can not send data through this c application. n i can not figure out why.