connect to external IP fails - c++

Question

I have been stuck with this problem for ages...
So I coded a game with multiplayer using the BSD sockets/Winsock 2 TCP. My server is up and working, I can connect to it locally (indirectly by filling in my own external ip). Everything seems to be fine. I tested with canyouseeme.org whether my ip and server port were properly port forwarded, and it was perfectly working. Then I sent my client to a friend to test it out by connecting to the server, and it failed all the time. I expected him to have connected, but I could not see anything on the server side (while canyouseenme.org even popped up as invalid client). I do not get it, do I have to do something special for external connecting in TCP?
Here is my connect function:
int CConnectSocket(CSocket s, unsigned short port, char* ipaddress)
{
SOCKADDR_IN target;
target.sin_family = AF_INET;
target.sin_port = htons(port);
target.sin_addr.s_addr = htonl(inet_addr(ipaddress));
if (connect(s, (SOCKADDR*)&target, sizeof(target)) == SOCKET_ERROR)
{
if (WSAGetLastError() == WSAEISCONN)
return CTCP_DONE;
else if (WSAGetLastError() != WSAEWOULDBLOCK && WSAGetLastError() != WSAEALREADY)
{
strcpy(inerr, "CConnectSocket: Failed to connect the socket. Error ");
char f[6];
sprintf(f, "%d", WSAGetLastError());
strcat(inerr, f);
return CTCP_ERROR;
}
return CTCP_WAIT;
}
return CTCP_DONE;
}
I keep looping this function until CTCP_DONE is returned (meaning I connected). My friend reported he timed out (so it returned CTCP_WAIT for too long). Again, I'm sure the client is the fault because my server was able to accept an external connection from canyouseeme.org. The IP address and port I fill in work because I can connect locally. If I change the port, local connection doesn't work anymore (proof that it is a correct argument). Changing the IP does yield the same result.
I appreciate any help! Hopefully I can solve this problem and begin the multiplayer.
EDIT
void CEngine::CSetSockAddr(CSockAddr* address, unsigned short port, char* ipaddress)
{
memset(address, 0, sizeof(CSockAddr));
address->sin_family = AF_INET;
address->sin_port = htons(port);
address->sin_addr.s_addr = htonl(inet_addr(ipaddress));
}
This is my socket address function. When I remove the htonl function, it works at my friend's side, but no at my side any more (I also host the server). My friend BTW uses XP, but since I called to use 2.2 WinSock that should be no issue. At least I hope that the setup function for WinSock guarantees a 2.2 implementation if it returns true.
EDIT 2
Hello guys,
I have got everything up and working now. It seems that if I add htonl I can connect as the host with the external IP rather than connecting with the loopback 127.0.0.0.1 or sth like that. So now I would like to know, how do I detect whether I am connecting to a server that I host? That would be a nice trick. Happy new year all!

Answer 1

Is very difficult to help you without a console... but you can talk with your friend and try this:
From your friend's PC, make a ping against your server.
If you recieve an answer, use tracert or traceroute to find out what's the problem
What's the route model of your friend? probably it has a System Event Log where you can check for rejected connections.
Luck!

Answer 2

You need to remove the htonl() call when calling inet_addr(). connect() expects the IP to be in network byte order, and inet_addr() returns the IP in network byte order, so there is no need to swap the bytes, on any platform.
Try this:
int CConnectSocket(CSocket s, unsigned short port, char* ipaddress)
{
SOCKADDR_IN target = {0};
target.sin_family = AF_INET;
target.sin_port = htons(port);
target.sin_addr.s_addr = inet_addr(ipaddress);
if (connect(s, (SOCKADDR*)&target, sizeof(target)) == SOCKET_ERROR)
{
int err = WSAGetLastError();
switch (err)
{
case WSAEISCONN:
return CTCP_DONE;
case WSAEWOULDBLOCK:
case WSAEALREADY:
return CTCP_WAIT;
default:
sprintf(inerr, "CConnectSocket: Failed to connect the socket. Error %d", err);
return CTCP_ERROR;
}
}
return CTCP_DONE;
}