This content originally appeared on DEV Community and was authored by Franklyne
When I first dove into cloud and DevOps, I naively assumed networking was as simple as “plug in a cable and go.” Spoiler alert: it’s not. Networking is the invisible backbone that holds everything together, and understanding it deeply is crucial for any modern DevOps engineer. Over the past 4 weeks, I embarked on a hands-on journey with Cisco Packet Tracer. What started as fumbling with virtual Ethernet cables morphed into designing a full three-router mesh network—each step revealing something vital about how networks truly work.
Along the way, I made plenty of rookie mistakes, learned some neat tricks, and gradually pieced together the bigger picture—from the humble crossover cable to the complexity of routing tables and serial connections.
Starting Small: The Basics Matter
The very first exercise had me connecting two PCs directly. I grabbed a straight-through cable—and nothing. PC0 wouldn’t ping PC1. Why? Because I’d forgotten that two similar devices need a crossover cable. That little slip was my first big lesson: the “right tool for the right job” is more than a cliché in networking; it’s the difference between a network that hums and one that’s dead silent. After some virtual cable-crimping and a lot of grumbling, finally seeing that first successful ping was oddly thrilling.
Next up, hubs versus switches. Connecting three PCs to a hub felt like joining a chaotic group chat where everyone sees every message—even ones not meant for them. Switches changed the game by learning MAC addresses and sending data only to its intended recipient, quietly speeding up communication. This idea stuck with me: efficiency in networking is less about raw speed and more about smartly directing traffic. It’s a principle I now apply when optimizing cloud virtual private clouds (VPCs) too.
Networking Grows Up: Services and Routers
By Exercise 3, I was no longer just plugging in cables—I was setting up network services. There was DHCP to auto-assign IP addresses (goodbye manual configurations), DNS to map friendly names to IPs, and even setting up an HTTPS and FTP server. I learned the hard way how DNS misconfigurations can bring down your services when my custom domain “deep-in-net.com” refused to load because I confused CNAME with A records. Now I always check DNS records first when something goes awry in the cloud.
Then came routers: the border control agents of your network. Exercise 4 introduced me to the concept of default gateways and subnets. I wasted 20 minutes staring at failed pings before realizing PCs need a map (the default gateway) to leave their local network. Understanding how routers operate at the network layer using IP addressing formed the foundation for grasping cloud concepts like VPC peering and cross-region routing.
Scaling Complexity: Multiple Switches and Routers
Exercises 5 and 6 stepped up the complexity. Two switches connected to several PCs linked by a single router showed me how switches keep traffic local, while routers handle cross-subnet communication. Testing connectivity across all devices felt like I was building a living, breathing network rather than just connecting machines.
Introducing a second router in Exercise 6 was when routing tables entered the picture. Manually managing static routes made me appreciate the intricate “GPS” that keeps data flowing efficiently. One typo sent my packets off into a digital abyss—but that mistake cemented why routing tables are so critical, especially when architecting cloud route tables in AWS or Azure.
The Final Stretch: Serial Cables and Mesh Networks
Exercise 7 brought serial DCE/DTE cables into play—basically, the network’s boss and intern. Forgetting to set the clock rate on the DCE cable left my link dead for 30 frustrating minutes. Such a small detail, yet so important. This experience taught me to triple-check even the tiniest config detail before blaming anything else, a habit that pays dividends when setting up VPN tunnels in the cloud.
Finally, Exercise 8 was the grand finale: a three-router mesh network with multiple subnets and PCs on each. I configured static routes meticulously to ensure every subnet talked to every other seamlessly. When I sent a ping from PC1 to PC11 and saw those precious “!” responses, I felt a proud sense of accomplishment. What started as a simple cable connection had blossomed into a scalable, efficient network.
Why This Journey Matters
Looking back, mastering Cisco Packet Tracer wasn’t just about learning a tool. It was about grasping the invisible foundations that make cloud and DevOps tick. As a DevOps engineer, my role isn’t just deploying containers or virtual machines—it’s about connecting these services intelligently and troubleshooting the network glue that binds them.
If you’re just starting out in DevOps or cloud and find networking intimidating, my advice is simple: start small and get your hands dirty with Cisco Packet Tracer. Expect to make mistakes and spend lots of time debugging. But each “ping” that goes through will build confidence and skills that make every future deployment smoother.
For those curious, I’ve documented all eight exercises in my embed GitHub repository, but truly, the best learning begins the moment you plug in that first virtual cable and hit ping.
Stay tuned for next week, when I’ll dive into administer a Linux server, set up security and network for a Ubuntu server, installing some popular services.
Until next time, happy networking, and keep experimenting!
This content originally appeared on DEV Community and was authored by Franklyne