Denial of Service (DoS) and Distributed Denial of Service (DDoS) attacks are common threats that every publicly accessible web server faces. The purpose of such attacks, in simplest terms, is to flood a server with connections, overloading it and preventing from accepting legitimate traffic. Step #1: SYNflood Protection A SYNflood attack is a DoS attack exploiting the TCP (Transmission Control Protocol) connection process itself. In basic terms, a TCP connection is established using a three-way handshake: The client (incoming connection) sends a synchronization packet (SYN) to the server. The server responds with a synchronization acknowledgement (SYN/ACK) to the client. The client then responds with an acknowledgement (ACK) back to the server. A SYNflood attack manipulates that three-way handshake by initiating multiple synchronization requests and then refusing to respond with any final acknowledgements. On a Linux server, you can quickly check for SYN packets by running thi
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