Preventing Network Outages with Pre-Change Planning

The scariest thing in most networks isn't a failure. It's a change. Console in, paste the config, hope the diff was what you thought it was. Forty-five minutes of a change window spent doing something a pipeline should have validated in four. Config as code fixes this — but only if the pipeline is real: pre-change validation, a rollback that's been tested, and a drift report that tells you when someone went around the process. Anything less is just a repo full of YAML. We've done this across Arista, Cisco and Juniper estates. The goal isn't fewer engineers. It's engineers who stop spending their evenings on change windows. What does a change window cost you today? #NetworkAutomation #Ansible #Arista #Cisco #NetDevOps

A lot of people connect a device to the network, receive an IP address, and never think about what is happening behind the scenes. In my latest video, I break down DHCP in plain language, including the DORA process: Discover → Offer → Request → Acknowledge I also walk through a hands-on Cisco Packet Tracer lab, configure a multilayer switch as the DHCP server, and verify the results from both the client and switch perspectives. The goal was to make the topic useful for someone just entering networking while still providing a practical refresher for experienced IT professionals. I also left in a real-world moment where I entered the wrong verification command, took a quick “TV timeout,” and came back with the correct one. Even experienced engineers do not type every command correctly the important part is understanding what you are trying to verify and knowing how to recover. Watch the full video here: https://lnkd.in/gjZaDhVD #Networking #DHCP #Cisco #PacketTracer #CCNA #ITTraining #NetworkEngineering

🚨 BREAKING: I have been defeated by a grocery store that does not exist. The plan was simple: "build a small enterprise network in Packet Tracer." Reasonable. Achievable. A Wednesday. Instead I have spent hours in a full blood feud with OSPF, who refuses to form neighbors with me for reasons it will not explain, like a router-shaped situation-ship. Packet Tracer's official stance: "Skill issue." My official stance: "Bet." THE CASUALTY LIST: 💀 VLANs — betrayed me first, as tradition demands 💀 Router-on-a-Stick — sounds like a fair ride, was not fun 💀 DHCP pools mid identity crisis, handing out addresses like they're improvising 💀 Subnetting — we've made peace, we don't talk about the war 💀 WAN links that link to nowhere, spiritually 💀 Cisco modules that apparently need DLC installed before they'll cooperate 💀 OSPF, deciding daily whether we are friends 💀 The realization that one (1) missing command can end your whole evening Peak moment: 45 minutes of deep, soul-searching troubleshooting to discover I forgot 'no shutdown' — Cisco's way of saying "I'd rather not" by default on every interface. My topology currently looks like a conspiracy board. Red string. Everywhere. I have theories now. So, as every engineer eventually does under pressure: ✨ Deleting everything and pretending this was the plan all along. ✨ ROUND 2. This time with: ✔️ actual architecture ✔️ documentation that isn't vibes ✔️ IP planning done BEFORE the chaos, not during ✔️ testing ✔️ marginally less emotional damage We are no longer doing a Packet Tracer lab. We are at war with a fictional grocery store, and only one of us is walking away with a green interface. If you hear cheering later, that's just me winning against a router. #Cisco #PacketTracer #CCNA #Networking #NetworkEngineering #LearningInPublic #OSPFIsMyVillainOriginStory #SendHelp

Continuing my Networking Refresher Series. This post focuses on Spine-Leaf Fabric Troubleshooting with practical Cisco and Juniper commands. A spine-leaf fabric should not be troubleshot randomly. The best approach is to follow the layers: Physical Links → Underlay Routing → Loopbacks → ECMP → MTU → Border/Services Leaf → Overlay Readiness → End-to-End Traffic In real production networks, many fabric issues come from simple but critical areas: interface errors, unstable underlay, missing loopback reachability, ECMP inconsistency, MTU mismatch, border leaf route issues, services path problems, or return-path failures. ▸ In real networks: Start from the foundation, validate each layer, and then prove the traffic path end to end. When the physical layer is clean, the underlay is stable, ECMP is healthy, and MTU is consistent, spine-leaf troubleshooting becomes much more predictable. "Follow me for more exciting Networking Refresher Series" "Comment PDF for a copy in your inbox" #SpineLeaf #Datacenter #NetworkTroubleshooting #NetworkEngineering #NetworkArchitecture #Cisco #Juniper #JUNOS #EVPN #VXLAN #BGP #CampusFabric

People think network engineers spend their day configuring routers. Reality? 40% Troubleshooting 30% Reading logs 20% Explaining issues to management 10% Actually making changes 😄 The longer I work in networking, the more I realize that technical knowledge gets you in the door, but troubleshooting methodology keeps you employed. Every outage teaches something a certification never could. What's one lesson you've learned from a production issue? #NetworkEngineer #Networking #Cisco #NetworkSecurity #BGP #OSPF #TechCareers #ITInfrastructure

🔥 Infrastructure Challenge #11 – The Mystery Network Latency Users across multiple offices report slow application performance. Monitoring shows: ✅ WAN links are healthy ✅ No packet loss detected ✅ CPU and Memory utilization are normal ✅ DNS resolution is working Yet application response times have increased from 50ms to 800ms. What would you investigate next? 👇 Share your troubleshooting approach. #Networking #CCNA #ITInfrastructure #NetworkEngineer #SysAdmin

🚨 Network War Room – Day 001 Can you identify the failing OSI layer before looking at the solution? Real-world network engineers don't guess—they troubleshoot methodically. Drop your answer (A, B, C, or D) in the comments before reading the explanation. Follow along as we tackle 260 Enterprise Networking Challenges, one incident at a time. #NetworkWarRoom #OSIModel #CCNA #NetworkEngineering #Cisco #Networking #Troubleshooting #LearnNetworking #Codenetworkz

🌐 What is DHCP? The Protocol That Makes Networking Easy! 🌐 📌 What DHCP Does ✅ Automatically assigns IP addresses to devices ✅ Eliminates manual configuration ✅ Reduces IP conflicts ✅ Simplifies network management ✅ Supports both IPv4 and IPv6 environments 🔄 The DORA Process Explained 1️⃣ Discover – Client searches for a DHCP server 2️⃣ Offer – Server offers an available IP address 3️⃣ Request – Client requests the offered IP 4️⃣ Acknowledge – Server confirms and assigns the IP 💡 Quick Facts 🔹 Uses UDP Ports 67 & 68 🔹 Supports DHCP Relay across subnets 🔹 Widely used in enterprise, campus, branch, and home networks 🔹 Essential for scalable network deployments #networking #technology

We took over a client's network last year that had no monitoring, no DR plan, and switches running firmware 3 versions behind. The previous provider had labelled it "stable." Six months in: 99.98% uptime, all critical patches applied, automated backups tested weekly, and the ops team stopped getting called at 3am. Nothing special about the hardware. The difference was having someone accountable for making it work — proactively, not reactively. Infrastructure isn't a set-it-and-forget-it problem. It needs operators. #managedIT #infrastructure

Last month we posted about bugs 👾 discovered in Cisco’s SD-WAN manager. Since then, yet another zero-day exploit has been exposed – the seventh this year!   As SD-WAN becomes increasingly critical to business operations, it’s important that your deployment is secure and reliable.   #cartika #beyondthemachine #cisco #sdwan