Re^2: TCP server: How to reject connections when busy?

[andal]

Don't rely on this part. Different implementations behave differently. For example Linux treats backlog parameter 0 as 3. In either case, when the queue is full, then the system simply stops answering SYN packets, which triggers their resending. As result, the peer gets no indication that your server is busy. It simply keeps waiting for connection to be established.