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🚨CISA Releases Guidance on Modern Approaches to Network Security🚨 The Cybersecurity and Infrastructure Security Agency (CISA), America's Cyber Defense Agency, and several partners have just released a comprehensive guide on modern approaches to network access security. This report emphasizes the limitations and vulnerabilities of traditional VPN solutions and advocates for adopting more robust and fine-grained security models like Secure Access Service Edge (SASE) and Secure Service Edge (SSE). Key Takeaways: 🔹 VPN Challenges: VPNs are prone to limitations while providing encrypted tunnels for remote access. These issues can expose organizations to significant risks and breaches. 🔹 Value of SASE & SSE: SASE and SSE focus on secure access to web services and applications, combining capabilities like Zero Trust Network Access, secure web gateways, and cloud access security brokers, ensuring all access is continuously verified. Together, they streamline security policies and offer seamless, secure access to data across hybrid environments. 🌐🔒 🔹 Implement Network Segmentation: Network segmentation is crucial for limiting the spread of attacks within an organization. Organizations can contain potential breaches and minimize the impact on critical systems by dividing the network into smaller, isolated segments. 🔀 🔹 Validate Vulnerability Scans on All Public-Facing Enterprise Assets: Regular vulnerability scans on public-facing assets are essential to identify and remediate potential security gaps. Ensuring that these scans are thorough and validated helps maintain a robust security posture and protects against external threats. 🛡️ Organizations transitioning from traditional VPNs to modern network access solutions can significantly benefit from the strategies and best practices outlined in this guide. Implementing these modern approaches strengthens security and aligns with Zero Trust principles, ensuring a more secure and resilient infrastructure. (Full disclosure: I participated in initial discussions about this guidance before leaving CISA earlier this year. Having been in the networking space for almost 30 years, this type of guidance is critical to help shape discussions on how network security is evolving and supports a Zero Trust mindset in new ways). #ZeroTrust #Technology #CloudComputing #SoftwareEngineering

🚀 Advanced Network Troubleshooting Using the TCP/IP Model 🛠️ Effective network troubleshooting requires a methodical approach, and the TCP/IP model is a perfect framework. Here's how to perform advanced diagnostics, layer by layer: 🔍 1. Physical Layer Start with the fundamentals. Always verify the hardware connection quality. ✅ Action: Inspect all network cables, ensure there are no loose connections, and confirm the integrity of ports. 💡 Pro Tip: Use link-state monitoring tools or hardware diagnostics to detect faulty cabling or port issues that might go unnoticed with a casual check. 🔍 2. Data Link Layer At this layer, network interface integrity is key. ✅ Action: Investigate the functionality of network interfaces (NICs) and switches. Ensure that MAC addressing and duplex settings are appropriately configured. 💡 Pro Tip: Utilize tools like Wireshark to inspect traffic patterns and detect any anomalies at Layer 2, such as broadcast storms or MAC address conflicts. 🔍 3. Network Layer Routing and IP configuration are crucial here. ✅ Action: Assess IP configurations (including subnet masks, default gateways, and routing tables). Ensure proper communication paths. 💡 Pro Tip: Advanced commands like tracert (Windows) or traceroute (Linux) can help diagnose routing issues and pinpoint where packets drop in transit. 🔍 4. Transport Layer Connectivity checks go beyond basic pings. ✅ Action: Test transport protocols (TCP/UDP). Ensure sessions are being properly established and maintained. 💡 Pro Tip: Use tools like netstat to analyze active connections and identify ports being used for communication, revealing potential firewall or service-based issues. 🔍 5. Application Layer Finally, validate that the application protocols are functioning as expected. ✅ Action: Analyze DNS, HTTP/HTTPS, and other services for latency or resolution issues. DNS misconfigurations can often mimic deeper network issues. 💡 Pro Tip: Tools like dig and nslookup can offer insights into DNS query responses. Advanced monitoring solutions such as APM tools (Application Performance Monitoring) can help track application performance bottlenecks. By leveraging these techniques and tools at each layer, you can systematically isolate and resolve even the most complex network issues. 💼💡 #AdvancedNetworking #TCPIP #NetworkEngineering #ITProfessional #TechLeadership #Infrastructure #NetworkSecurity #ITInnovation #CCNA #CCNP

𝗦𝗣𝗔𝗡, 𝗥𝗦𝗣𝗔𝗡 𝗮𝗻𝗱 𝗻𝗲𝘁𝘄𝗼𝗿𝗸 𝘁𝗮𝗽𝘀 All three can feed traffic to a monitoring tool. They do not provide the same level of visibility confidence. ▪️ 𝗦𝗣𝗔𝗡 𝗽𝗼𝗿𝘁 SPAN creates a switch-based copy of selected local traffic. It is convenient and inexpensive, but the mirrored copy depends on: ✓ Switch resources ✓ Destination-port bandwidth ✓ Correct SPAN configuration ✓ Traffic volume and oversubscription Under load, mirrored packets may be dropped. The monitoring tool may also observe altered timing or packet order. ▪️ 𝗥𝗦𝗣𝗔𝗡 RSPAN—Cisco’s term for Remote SPAN—transports mirrored traffic across an RSPAN VLAN to another switch. It extends monitoring reach, but also adds dependence on: ✓ The transit switching path ✓ VLAN configuration ✓ Available bandwidth ✓ Every intermediate device RSPAN inherits the limitations of SPAN and introduces more configuration complexity. ▪️ 𝗡𝗲𝘁𝘄𝗼𝗿𝗸 𝘁𝗮𝗽 A network tap creates a dedicated hardware copy of traffic independently of the switch’s SPAN configuration. It generally provides more faithful passive visibility and is often preferred at critical OT monitoring points. Some tap designs are fail-open, but this depends on the specific device and architecture. 𝗖𝗼𝗿𝗲 𝗰𝗼𝗻𝗰𝗲𝗽𝘁 𝗦𝗣𝗔𝗡 mirrors locally through switch resources. 𝗥𝗦𝗣𝗔𝗡 transports that mirrored traffic across a switching path. 𝗔 𝗻𝗲𝘁𝘄𝗼𝗿𝗸 𝘁𝗮𝗽 creates a dedicated hardware copy. For convenient monitoring, SPAN may be sufficient. For high-confidence OT detection and incident investigation, a correctly designed tap architecture is usually the stronger choice. #OTSecurity #NetworkMonitoring #NetworkTap #SPAN #RSPAN #IndustrialCybersecurity

A CISO spent two years building what they believed was a world-class internal security programme. MFA everywhere. EDR deployed. Patching at 95%. SOC running 24/7. The breach came through their HVAC vendor. Not a nation-state. Not a zero-day. A heating and ventilation contractor with network access, default credentials, and zero security requirements in their contract. The forensics told the story: → Vendor granted network access 3 years earlier for remote monitoring → Access never scoped - full network segment visibility → Vendor credentials never rotated → Vendor had suffered their own breach 6 months prior - the CISO never knew → Attacker used vendor credentials to move laterally across the network → 14 days inside the environment before detection During the investigation, the CISO pulled the full vendor access list. 214 third parties had active credentials to company systems. Security had reviewed 12 of them. The other 202 had been granted access by IT, operations, finance, and facilities — without a single security check. Post-incident board meeting: "How did an HVAC vendor have access to our core network?" "Three years ago someone in facilities needed remote monitoring set up before the weekend. IT obliged." "Why didn't security know?" "Nobody told us. And we never asked." The organisation had a vendor management process. Procurement owned it. Legal reviewed contracts. Finance approved invoices. Nobody owned security requirements. What changed: → All 214 vendors audited - 67 had access immediately revoked, no longer active → Remaining vendors tiered by risk: critical, high, medium, low → Critical vendors: annual security assessment, quarterly access review → All new contracts: mandatory security requirements as standard clause → All vendor access: scoped, time-limited, monitored by default Twelve months later a critical-tier vendor detected a breach in their own environment and notified the company immediately. For the first time - the CISO found out before the attacker used it. The lesson: the attack surface doesn't end at the organisation's perimeter. It ends at the weakest vendor with a credential to the network. How many third parties have active access to your systems right now? Do you know the answer? SOC(k)s hit hard courtesy of Ontinue #cybersecurity #ciso #supplychain #technology #access #remoteaccess #critical #it

🔍 Cisco Troubleshooting Mastery: Essential Commands for Network Professionals When network issues arise, efficiency is critical. Below is a structured approach to Cisco device troubleshooting using proven CLI commands: 🌐 Core System Diagnostics show version - Verify IOS version, uptime, and hardware show ip interface brief - Instant interface status overview show logging - Critical system events and errors 🛡️ First Hop Redundancy Protocols show standby brief (HSRP) show vrrp brief show glbp brief 📊 Routing Protocol Troubleshooting EIGRP: show ip eigrp neighbors + debug eigrp packets OSPF: show ip ospf neighbor + debug ospf adj BGP: show ip bgp summary + debug bgp updates 🔒 Security & VPN Diagnostics IPSec: show crypto isakmp sa + show crypto ipsec sa 802.1X: show dot1x all + dot1x test eapol-capable ⚡ Pro Techniques 1️⃣ Filter outputs: | include/exclude/section 2️⃣ Timestamps: service timestamps debug datetime msec 3️⃣ Baseline comparison: show run | archive config differences #CiscoNetworking #NetworkEngineering #ITInfrastructure #Troubleshooting #CCNP #CCIE #NetworkAutomation #TechOps #NetworkAdministration #IPSec #RoutingProtocols

A Smarter Way to Evaluate Vendors Over the years, I've assessed hundreds of vendors - from global tech giants to niche consultancies — all making bold claims about capability, speed, and impact. To cut through the noise, I developed a simple evaluation lens: the CECE framework. 1. Capability - Does the organisation have the capabilities to deliver what we need - methodologies, research & development investment, frameworks, approaches, quality management - their IP? What do they bring to the table beyond the people and the product? 2. Experience - Have they done the thing we want them to do for similar customers, in similar industries and similar scale? Do they say "we would do it this way" more than "we have done it this way before"? 3. Capacity - Do they have the people, technical scale, and staying power? It's not just about headcount, it's also about their ability to absorb risk and scale when needed, both in size and reach. 4. Expertise - Do they have the smartest people with the skills and qualifications you need? Do they continue to invest in their people or do they rely on what they brought with them when they joined? Keep in mind, this framework evaluates your confidence in the vendor as a partner, and sits above the “requirements vs. proposed solution, price, etc” RFx evaluation. What else would you include?

In today’s always-on world, downtime isn’t just an inconvenience — it’s a liability. One missed alert, one overlooked spike, and suddenly your users are staring at error pages and your credibility is on the line. System reliability is the foundation of trust and business continuity and it starts with proactive monitoring and smart alerting. 📊 𝐊𝐞𝐲 𝐌𝐨𝐧𝐢𝐭𝐨𝐫𝐢𝐧𝐠 𝐌𝐞𝐭𝐫𝐢𝐜𝐬: 💻 𝐈𝐧𝐟𝐫𝐚𝐬𝐭𝐫𝐮𝐜𝐭𝐮𝐫𝐞: 📌CPU, memory, disk usage: Think of these as your system’s vital signs. If they’re maxing out, trouble is likely around the corner. 📌Network traffic and errors: Sudden spikes or drops could mean a misbehaving service or something more malicious. 🌐 𝐀𝐩𝐩𝐥𝐢𝐜𝐚𝐭𝐢𝐨𝐧: 📌Request/response counts: Gauge system load and user engagement. 📌Latency (P50, P95, P99):  These help you understand not just the average experience, but the worst ones too. 📌Error rates: Your first hint that something in the code, config, or connection just broke. 📌Queue length and lag: Delayed processing? Might be a jam in the pipeline. 📦 𝐒𝐞𝐫𝐯𝐢𝐜𝐞 (𝐌𝐢𝐜𝐫𝐨𝐬𝐞𝐫𝐯𝐢𝐜𝐞𝐬 𝐨𝐫 𝐀𝐏𝐈𝐬): 📌Inter-service call latency: Detect bottlenecks between services. 📌Retry/failure counts: Spot instability in downstream service interactions. 📌Circuit breaker state: Watch for degraded service states due to repeated failures. 📂 𝐃𝐚𝐭𝐚𝐛𝐚𝐬𝐞: 📌Query latency: Identify slow queries that impact performance. 📌Connection pool usage: Monitor database connection limits and contention. 📌Cache hit/miss ratio: Ensure caching is reducing DB load effectively. 📌Slow queries: Flag expensive operations for optimization. 🔄 𝐁𝐚𝐜𝐤𝐠𝐫𝐨𝐮𝐧𝐝 𝐉𝐨𝐛/𝐐𝐮𝐞𝐮𝐞: 📌Job success/failure rates: Failed jobs are often silent killers of user experience. 📌Processing latency: Measure how long jobs take to complete. 📌Queue length: Watch for backlogs that could impact system performance. 🔒 𝐒𝐞𝐜𝐮𝐫𝐢𝐭𝐲: 📌Unauthorized access attempts: Don’t wait until a breach to care about this. 📌Unusual login activity: Catch compromised credentials early. 📌TLS cert expiry: Avoid outages and insecure connections due to expired certificates. ✅𝐁𝐞𝐬𝐭 𝐏𝐫𝐚𝐜𝐭𝐢𝐜𝐞𝐬 𝐟𝐨𝐫 𝐀𝐥𝐞𝐫𝐭𝐬: 📌Alert on symptoms, not causes. 📌Trigger alerts on significant deviations or trends, not only fixed metric limits. 📌Avoid alert flapping with buffers and stability checks to reduce noise. 📌Classify alerts by severity levels – Not everything is a page. Reserve those for critical issues. Slack or email can handle the rest. 📌Alerts should tell a story : what’s broken, where, and what to check next. Include links to dashboards, logs, and deploy history. 🛠 𝐓𝐨𝐨𝐥𝐬 𝐔𝐬𝐞𝐝: 📌 Metrics collection: Prometheus, Datadog, CloudWatch etc. 📌Alerting: PagerDuty, Opsgenie etc. 📌Visualization: Grafana, Kibana etc. 📌Log monitoring: Splunk, Loki etc. #tech #blog #devops #observability #monitoring #alerts

SNMP is commonly used for network monitoring... But is model driven telemetry better? SNMP has been the de facto standard for network monitoring for over 34 years. SNMP: → pull-based (only gets device info when queried) → frequent polling can add strain to your network → difficult to provide "real-time" responses But as network deployments grow, and traffic needs increase - SNMP polling has trouble scaling. Model driven telemetry is a newer approach that is becoming the preferred method for monitoring. Model driven telemetry: → reduces bandwidth and CPU overhead → very efficient to send to multiple recipients → data can be sent periodically or on an event trigger → push model (data flows continuously to subscribers) As more devices support telemetry it's becoming more practical to use across your network. Overall, telemetry gives you more data, with better performance. P.S. Have you tried using model driven telemetry? What do you think?

Step-by-step process to troubleshoot routing and switching issues in networks for network engineer: 1. **Gather Information:** - Understand the reported problem. - Collect network diagrams, configurations, and any recent changes. 2. **Physical Layer Check:** - Verify cable connections, interfaces, and physical components. - Ensure devices are powered on and functioning. 3. **Basic Connectivity Tests:** - Use tools like `ping`, `traceroute`, or `arp` to test connectivity between devices. - Check for connectivity issues between specific network segments. 4. **Check Device Configurations:** - Verify device configurations for routing tables, VLAN settings, access control lists (ACLs), etc. - Look for any misconfigurations or inconsistencies. 5. **Routing Protocols:** - Verify if routing protocols (OSPF, BGP, etc.) are correctly configured and neighbors are established. - Check routing tables for correct information and route advertisements. 6. **Switching Configuration:** - Review VLAN configurations, spanning-tree settings, and port configurations. - Ensure proper VLAN tagging and trunking between switches. 7. **Traffic Analysis:** - Use network monitoring tools to analyze traffic patterns, identify bottlenecks, or anomalies. - Look for excessive broadcasts, collisions, or errors. 8. **Hardware Diagnostics:** - Check hardware health using device-specific diagnostic commands. - Look for hardware-related errors or failures in logs. 9. **Firmware/Software Updates:** - Ensure devices are running the latest firmware/software versions to address known bugs or issues. 10. **Isolation Testing:** - Temporarily isolate segments or devices to narrow down the problematic area. - Verify if the problem persists within the isolated segment. 11. **Collaboration and Documentation:** - Collaborate with colleagues or vendor support if needed. - Document each step taken, changes made, and their effects. 12. **Implement Solutions:** - Apply fixes or configuration changes based on identified issues. - Test to confirm that the problem has been resolved. 13. **Monitor and Follow-up:** - Monitor the network after changes to ensure stability and functionality. - Follow up with users or stakeholders to confirm resolution. #troubleshooting #routingandswitching #ccna #ccnp #networkengineer

Friday networking reminder: Don’t troubleshoot the symptom. Troubleshoot the path. When a user says, "The network is down," that does not automatically mean the network is the problem. It could be: • A physical-layer issue • A VLAN mismatch • A spanning-tree change • A failed gateway • A routing problem • A bad circuit • A power issue at the remote site • Or an application failure that only looks like a network outage. One of the biggest lessons I’ve learned in over 16 years of supporting enterprise networks is this: Start at Layer 1, verify the facts, and work your way up. Check the interface. Check the errors. Check the VLAN. Check the gateway. Check the route. Check the path. Then confirm the fix. Strong network engineers do not just know commands. They know how traffic should flow, where it can break, and how to isolate the failure without guessing. My advice to anyone growing in networking: Build labs, break things on purpose, and practice explaining what happened. That is how commands turn into real troubleshooting skills. Happy Friday to everyone keeping the packets moving.