c++ winsock server-client remote connection - c++

Question

I am trying to create a simple app that exchanges messages between two remote computers.
With the "127.0.0.1" ip it works properly, waits for the client's confirm and connects to the client, but if I try a local "192.168.0.15" or my global ip with the same port, the server connects immediately to sth without waiting for the client.
Here's part of my server code:
char ip[20] = "127.0.0.1"; int port = 19385;
SOCKET sockListen, sockConnect;
SOCKADDR_IN address;
sockConnect = socket (AF_INET, SOCK_STREAM, NULL);
address.sin_addr.s_addr = inet_addr (ip);
address.sin_family = AF_INET;
address.sin_port = htons (port);
sockListen = socket (AF_INET, SOCK_STREAM, NULL);
bind (sockListen, (SOCKADDR*)&address, AddressSize);
listen (sockListen, SOMAXCONN);
sockConnect = accept (sockListen, (SOCKADDR*)&address, &AddressSize);
...
Please suggest how to fix the problem. thx

Answer 1

You are not supposed to initialize your sockConnect variable with socket() before calling accept(). accept() returns a new allocated socket handle that is already connected to a client. You are leaking the socket handle that socket() allocated.
You can only bind() to an IP that belongs to a NIC of the local machine that the app is running on. You cannot bind() to an external IP.
The code you have shown is not doing any error handling at all. You need to add that, eg:
int errCode;
SOCKET sockListen = socket (AF_INET, SOCK_STREAM, NULL);
if (sockListen == INVALID_SOCKET)
{
errCode = WSAGetLastError();
// ...
}
else
{
SOCKADDR_IN address = {0};
address.sin_addr.s_addr = inet_addr (ip);
address.sin_family = AF_INET;
address.sin_port = htons (port);
if (bind (sockListen, (SOCKADDR*)&address, sizeof(address)) == SOCKET_ERROR)
{
errCode = WSAGetLastError();
// ...
}
else
{
if (listen (sockListen, SOMAXCONN) == SOCKET_ERROR)
{
errCode = WSAGetLastError();
// ...
}
else
{
int addressSize;
SOCKET sockClient = accept (sockListen, (SOCKADDR*)&address, &addressSize);
if (sockClient == INVALID_SOCKET)
{
errCode = WSAGetLastError();
// ...
}
else
{
// ...
closesocket(sockClient);
}
}
}
closesocket(sockListen);
}