winsock error 10049 trying to bind - c++

Question

I have a problem with server connection. When I try to bind the server to my external device IP I got a winsock error: 10049 Cannot assign requested address. Using localhost server works correctly.
This IP address: 192.168.0.202 ping successfully.
I worked on win8.1. I turned off firewall and windows defender and it did not help.
Code with server implementation has been taken from http://www.planetchili.net/forum/viewtopic.php?f=3&t=3433
#include "Server.h"
Server::Server(int PORT, bool BroadcastPublically) //Port = port to broadcast on. BroadcastPublically = false if server is not open to the public (people outside of your router), true = server is open to everyone (assumes that the port is properly forwarded on router settings)
{
//Winsock Startup
WSAData wsaData;
WORD DllVersion = MAKEWORD(2, 1);
if (WSAStartup(DllVersion, &wsaData) != 0) //If WSAStartup returns anything other than 0, then that means an error has occured in the WinSock Startup.
{
MessageBoxA(NULL, "WinSock startup failed", "Error", MB_OK | MB_ICONERROR);
exit(1);
}
addr.sin_addr.s_addr = inet_addr("192.168.0.202");
addr.sin_port = htons(1234); //Port
addr.sin_family = AF_INET; //IPv4 Socket
sListen = socket(AF_INET, SOCK_STREAM, NULL); //Create socket to listen for new connections
if (bind(sListen, (SOCKADDR*)&addr, sizeof(addr)) == SOCKET_ERROR) //Bind the address to the socket, if we fail to bind the address..
{
std::string ErrorMsg = "Failed to bind the address to our listening socket. Winsock Error:" + std::to_string(WSAGetLastError());
MessageBoxA(NULL, ErrorMsg.c_str(), "Error", MB_OK | MB_ICONERROR);
exit(1);
}
if (listen(sListen, SOMAXCONN) == SOCKET_ERROR) //Places sListen socket in a state in which it is listening for an incoming connection. Note:SOMAXCONN = Socket Oustanding Max Connections, if we fail to listen on listening socket...
{
std::string ErrorMsg = "Failed to listen on listening socket. Winsock Error:" + std::to_string(WSAGetLastError());
MessageBoxA(NULL, ErrorMsg.c_str(), "Error", MB_OK | MB_ICONERROR);
exit(1);
}
serverptr = this;
}
bool Server::ListenForNewConnection()
{
SOCKET newConnection = accept(sListen, (SOCKADDR*)&addr, &addrlen); //Accept a new connection
if (newConnection == 0) //If accepting the client connection failed
{
std::cout << "Failed to accept the client's connection." << std::endl;
return false;
}
else //If client connection properly accepted
{
std::cout << "Client Connected! ID:" << TotalConnections << std::endl;
Connections[TotalConnections] = newConnection; //Set socket in array to be the newest connection before creating the thread to handle this client's socket.
CreateThread(NULL, NULL, (LPTHREAD_START_ROUTINE)ClientHandlerThread, (LPVOID)(TotalConnections), NULL, NULL); //Create Thread to handle this client. The index in the socket array for this thread is the value (i).
//std::string MOTD = "MOTD: Welcome! This is the message of the day!.";
//SendString(TotalConnections, MOTD);
TotalConnections += 1; //Incremenent total # of clients that have connected
return true;
}
}
bool Server::ProcessPacket(int ID, Packet _packettype)
{
switch (_packettype)
{
case P_ChatMessage: //Packet Type: chat message
{
std::string Message; //string to store our message we received
if (!GetString(ID, Message)) //Get the chat message and store it in variable: Message
return false; //If we do not properly get the chat message, return false
//Next we need to send the message out to each user
for (int i = 0; i < TotalConnections; i++)
{
if (i == ID) //If connection is the user who sent the message...
continue;//Skip to the next user since there is no purpose in sending the message back to the user who sent it.
if (!SendString(i, Message)) //Send message to connection at index i, if message fails to be sent...
{
std::cout << "Failed to send message from client ID: " << ID << " to client ID: " << i << std::endl;
}
}
//std::cout << "Processed chat message packet from user ID: " << ID << std::endl;
if(Message == "go")
std::cout << "MESSAGE:GO!" << std::endl;
else if(Message == "left")
std::cout << "MESSAGE: GO LEFT!" << std::endl;
else if (Message == "right")
std::cout << "MESSAGE:GO RIGHT!" << std::endl;
else
std::cout << "MESSAGE:DO NOTHING!" << std::endl;
break;
}
default: //If packet type is not accounted for
{
std::cout << "Unrecognized packet: " << _packettype << std::endl; //Display that packet was not found
break;
}
}
return true;
}
void Server::ClientHandlerThread(int ID) //ID = the index in the SOCKET Connections array
{
Packet PacketType;
while (true)
{
if (!serverptr->GetPacketType(ID, PacketType)) //Get packet type
break; //If there is an issue getting the packet type, exit this loop
if (!serverptr->ProcessPacket(ID, PacketType)) //Process packet (packet type)
break; //If there is an issue processing the packet, exit this loop
}
std::cout << "Lost connection to client ID: " << ID << std::endl;
closesocket(serverptr->Connections[ID]);
return;
}
Any ideas?

Answer 1

The bind() function is used to specify which address of the server system is used to accept connections from remote clients, not to specify which remote client is allowed to connect to the server. The bind() function can only be used with addresses that are valid for the server itself, not for addresses of remote devices or hosts.
In order to limit which remote host is allowed to connect to your server, you need to accept the connection and validate the remote address at that time. If the address is not the correct one, the connection is closed.
In general, you want to use INADDR_ANY unless your server is multi-homed (more than one physical connection to more than one network), and only then if you are trying to restrict connections to one of the networks to which your server is attached.

Answer 2

Winsock returns the error flag 10049 (WSAEADDRNOTAVAIL) through its API WSAGetLastError whenever an application tries to bind to an invalid ip Addrress.
binding to a specific IP address means that whenever you run the program (server) the address should be valid (available) but however DHCP gives you dynamic ip addresses everytime you disconnect/connect your adapter so you the address you bound the server the previous time is not valid to correct it open cmd and enter :
ipconfig
you'll get the list of ip4/ip6 addresses then you can pick one of them and bind your server to however this method is really dull so the alternative is to bind to INADDR_ANY so you let the system do the job for you.
you need only from the client to enter the server address and port and connect.