handshake / socket error

[lothiex]

Hello, I installed the files you shared on a dedicated server, but I can’t connect from my own computer. It stays on “connecting” and shows handshake / socket error. I think I did everything correctly: I built the client in release, extracted mob proto and item proto from the server files and added them to the locale, and the IP address is correct. When I stop the server it gives connection error, when I start it it stays on connecting. What should I do? Can you help me?

[Metin2BTP]

@lothiex

Fix: select(0, ...) in fdwatch.cpp breaks all networking on Linux

Root cause: In src/libthecore/fdwatch.cpp, the fdwatch() function passes 0 as the first argument to select():

r = select(0, &fdw->working_rfd_set, &fdw->working_wfd_set, (fd_set*) 0, &tv);

On Windows, the nfds parameter is ignored, so this works fine. On Linux/FreeBSD, nfds must be the highest file descriptor + 1. Passing 0 means zero file descriptors are monitored — select() returns immediately, write events never trigger, and outgoing data (including the KeyChallenge handshake) sits in the output buffer forever.

Symptoms: Client connects (TCP handshake succeeds), server logs KeyChallenge sent, but the client never receives it. Connection hangs on "You will be connected to the server..." until the handshake timeout kicks in.

Fix (lines 366 and 371):

// Before select(), compute nfds from tracked fds
int nfds = 0;
for (i = 0; i < fdw->nselect_fds; ++i)
{
    if ((int)fdw->select_fds[i] >= nfds)
        nfds = (int)fdw->select_fds[i] + 1;
}

r = select(nfds, &fdw->working_rfd_set, &fdw->working_wfd_set, (fd_set*) 0, &tv);

After this one-line change, the KeyChallenge handshake completes and login works normally.