Network Layer
Explore the Network Layer (Layer 3) of the OSI model, focusing on IPv4 and IPv6, IP addressing, routing, and how routers forward packets using destination IPs.
Transport Layer
In this lesson, we examine the 4th layer of the OSI model called the Transport Layer. There are a few protocols that operate at the Transport layer. However, by far the most widely used ones are TCP and UDP.
Application Layer
In this lesson, we examine the top three layers of the OSI model, layers 5, 6, and 7, called the Application, Presentation, and Session.
Network Fundamentals
Learn networking basics with the Network Fundamentals course. Build a CCNA-ready foundation through clear lessons, labs, and real Cisco practice.
Understanding the OSI model
In this lesson, we explain what the OSI model is in an easy and understandable language. It is one of the most important concepts in networking, so we break it down into pieces to help you understand exactly what its purpose is.
Standard Numbered ACL
Learn how Standard Numbered IPv4 ACLs work. This lesson covers packet matching, wildcard masks, implicit "deny any," and configuring ACLs with global or named-style commands.
ACL Basics
ACL Basics: Learn how access control lists match and manage traffic on Cisco devices.
HTTP and DNS essentials
This lesson continues our exploration of TCP/IP protocols that are important in the context of Access Control Lists (ACLs). It explores the most common use of the Internet: browsing the World Wide Web (www).
TCP and UDP essentials
This lesson begins our discussions on the fundamentals of Layer 4 (Transport Layer) and Layer 7 (Application Layer) protocols. This knowledge will serve you as a context required to understand how Access Control Lists (ACLs) work.
Final Troubleshooting Lab
Troubleshooting is one of the hardest parts of networking, especially in real environments. The truth is, you can't fully learn how to troubleshoot just by reading books or watching a video tutorial. It takes hands-on practice and real-world experience.