GUIDES MEET PRACTICE
Clear networking guides and 68 CCNA browser labs. Learn the concepts, practice IOS-style commands, and check your work as you go.
One lab free. No account, installation, or hardware needed.
A browser simulation of selected IOS behavior. It does not run an IOS image.
EXPLORE THE LIBRARY
Models, addresses, and the basics that connect everything.
↗ 02Switching & VLANsBuild and troubleshoot Layer 2 networks.
↗ 03RoutingUnderstand forwarding decisions and paths.
↗ 04Security & accessExplore controls, authentication, and firewalls.
↗ 05WirelessFrom WLAN fundamentals to controller operations.
↗ 06Linux & toolsDiagnose and verify from the command line.
↗FREE FIELD REFERENCES
A free PingLabz account unlocks the Linux, ASA, BGP, and OSPF PDFs. Choose the guide you need and keep it close while you practice.
GO FURTHER WITH PRO
Pro unlocks 60 build labs, six troubleshooting labs, and the campus Mega Lab. Follow guided exercises, try IOS-style commands, and check your configuration as you go.
SELECTED READING
Keep learning
The three-way handshake is the first thing anyone learns about TCP and the last thing most people actually look at. SYN, SYN-ACK, ACK is easy to draw. What is harder, and far more useful, is reading a real
Discover, Offer, Request, Ack. You can recite DORA in your sleep, and it still will not help you the day a client comes up with a 169.254 address and the server insists the pool is fine. What helps is
Every OSPF adjacency you have ever built started with a Hello packet, and almost every adjacency that refuses to build is a Hello packet being quietly thrown away. The trouble is that show ip ospf neighbor only tells you the
Two monitoring platforms, one Ubuntu box, zero port collisions. Plus the built-in host that cannot reach its own agent, and why apt was not an option.
From an empty Ubuntu box to a Grafana login screen: APT repo, systemd, and the 20-second gotcha that makes people think the install failed.
Ten printable pages of Linux networking commands, flags and real lab output, including a ten-symptom troubleshooting decision tree. Free for members.
Every Linux networking command that matters, grouped by the question it answers, with real captures from a four-hop lab and the triage order to run them in.
Enable ufw without losing your SSH session, learn the rule grammar, and see exactly which iptables chains it builds underneath.
Your iptables rules already run on nftables. Handles, named sets, inet tables and atomic ruleset loads, all proven with real output from a live lab.
Tables, chains and rule order, demonstrated with real captures from a Debian host in a live lab: DROP against REJECT timing, conntrack, logging and NAT.
Every Linux networking tool is a formatter over a handful of kernel files. Here is what is in them, how to read the hex, and what happens when you change the sysctls that matter.
Five live bandwidth monitors pointed at the same flow at the same time, with real terminal frames and a reconciliation of why they all report different numbers.