Terminology Index
Glossary
2953 terms
Three-Way Handshake
The TCP setup exchange (SYN, SYN-ACK, ACK) that establishes a connection between two endpoints. Foundational to understanding networking and to recognizing many TCP-based attack patterns.
TCP's three-way handshake establishes a reliable connection: the initiator sends SYN, the responder replies SYN-ACK, the initiator confirms with ACK. Recognizing it is foundational networking literacy and matters for defenders: SYN floods, half-open connection abuses, and reconnaissance scans all manifest as specific patterns at this layer. Reading packet captures, interpreting firewall logs, and analyzing connection-rate anomalies all start from understanding this handshake.
Introduced in: Networking Foundations
Examples
- Reading a packet capture showing the SYN, SYN-ACK, ACK exchange.
- Recognizing a SYN flood by half-open connections piling up.
- Interpreting connection-rate anomalies via TCP-handshake patterns.
