# How TCP Handshake Works

DevFeed: [How TCP Handshake Works](<https://devfeed.tech/articles/how-tcp-handshake-works-34678.md>)

Original publisher: [Read original article](<https://newsletter.systemdesigncodex.com/p/how-tcp-handshake-works>)

Author: Saurabh Dashora

Published: 2026-03-31T08:17:52Z

Content type: tutorial

Language: en

Sources: [System Design Codex](<https://devfeed.tech/sources/system-design-codex.md>)

Topics: [Handshake](<https://devfeed.tech/topics/handshake.md>), [client](<https://devfeed.tech/topics/client.md>), [servers](<https://devfeed.tech/topics/servers.md>)

Tags: [client](<https://devfeed.tech/tags/client.md>), [communication](<https://devfeed.tech/tags/communication.md>), [http-3](<https://devfeed.tech/tags/http-3.md>), [quic](<https://devfeed.tech/tags/quic.md>), [sequence](<https://devfeed.tech/tags/sequence.md>), [server](<https://devfeed.tech/tags/server.md>), [tcp](<https://devfeed.tech/tags/tcp.md>), [tcp-handshake](<https://devfeed.tech/tags/tcp-handshake.md>)

## AI overview

A tutorial explaining the TCP three-way handshake. It describes how a client sends SYN, a server responds with SYN-ACK, and the client completes the connection with ACK, including the role of initial sequence numbers and control flags.

## Source excerpt

The 3 step process