What does a SYN packet indicate?

• A. The server is refusing a connection.
• B. A request to initiate a TCP connection.
• C. Data transfer is starting.
• D. The connection is already established.

Answer: (B)

A SYN packet signals a request to start a TCP connection. In TCP, connections are established with a three‑way handshake, and the first step is a segment with the SYN flag set from the initiator. This tells the other side, “let’s begin a connection and synchronize sequence numbers.” The expected follow‑up is a SYN‑ACK from the recipient, and then an final ACK from the initiator to complete the handshake. No actual data is transferred during this exchange; data transfer only begins after the handshake is finished. If a host wants to refuse a connection, it would typically reply with a reset (RST) rather than continuing the handshake. So a SYN is all about initiating the connection setup, not about data transfer or an already established state.