It's mentioned in the prose. After bind() before connect() there is a race condition, you can receive packets going to unconnected bind() socket, right? bin

It's mentioned in the prose. After bind() before connect() there is a race condition, you can receive packets going to unconnected bind() socket, right? bind(0.0.0.0, 1234) ## packet to port 1234 arrives NOW connect(1.1.1.1, 53) If you recv() you will not be able to figure out if the received packet came from 1.1.1.1 or someone else. Therefore in case of bind+connect you must use recvfrom and validate source of the packet, at least for early packets on the socket.