Learn network fundamentals to have cutting-edge skills and hands-on experience to excel in any DevOps role.

DevOps for Developers

Learn network fundamentals essential for any DevOps specialist. You'll explore socket programming, command-line tools, OSI layer protocols, and more.

Network Fundamentals

A TCP connection is established by using a **three-way handshake**, which we briefly touched upon in a previous lesson. The connection establishment phase uses the **sequence number**, the **acknowledgment number**, and the **SYN flag**. 

# Initiating a Connection
When a client host wants to **open a TCP connection** with a server host, it creates and sends a TCP segment with:

- The *SYN* flag set
- The sequence number set to a random initial value. So the sequence numbers **do not start with 0**! Can you guess why?


In this lesson, we'll discuss how a TCP connection is established!

Before We Begin

Internet and the OSI Model

The Application Layer

The Transport Layer

An Introduction to Socket Programming with Python

The Network Layer

The Link Layer

Conclusion

TCP Connection Establishment: Three-way Handshake

Initiating a Connection