What Is TCP/IP? How Does TCP/IP Work?
Get a high-level overview of the TCP/IP model, how packets move through the stack, and how it relates to the OSI model.
TCP/IP Overview
TCP/IP is the suite of communication protocols that powers the modern internet. It consists of layered protocols such as IP for addressing and routing, TCP and UDP for transport, and higher-level protocols like HTTP, DNS, and SMTP that applications use.
Rather than strictly matching the seven-layer OSI model, TCP/IP groups functions into fewer layers: link, internet, transport, and application. Understanding where each protocol fits helps you troubleshoot problems and design networks more effectively.
Core TCP/IP Troubleshooting Commands
Networking issues rarely announce which layer is broken. Using a small set of diagnostic commands, you can quickly trace problems from the local interface out to remote servers. Combining ipconfig or ifconfig with ping, traceroute, and netstat gives you a strong toolkit for everyday debugging.
For more advanced analysis, commands like netstat and ss show which ports are in use, while tools such as tcpdump and Wireshark provide packet-level insight.
Run these when diagnosing connectivity issues.
ipconfig /all
ping 8.8.8.8
tracert www.example.com
netstat -ano
Use Terminal to gather quick diagnostics.
ifconfig
ping 8.8.8.8
traceroute www.example.com
netstat -an | head