N4N057: The Art of Troubleshooting

In this episode of NS for Networking, Ethan Banks leads a detailed walkthrough of his troubleshooting methodology, prompted by a listener question. The episode begins with the foundational mindset principle: don't be defensive when a network problem is reported. Ethan argues that network failures are not personal failures, and that engineers must approach problems with open curiosity rather than ego-driven defensiveness. Holly Podbilak adds that even long-trusted vendors and technologies can fail, reinforcing the need for open-mindedness.

The first actionable step is to gather information thoroughly before attempting any fix. Ethan stresses that trouble tickets are often inaccurate, exaggerated, or speculative. Engineers must investigate the who, what, when, and where of a problem to understand its true scope. A common example discussed is users reporting 'the network is down' when in fact only a single application is unavailable. Holly reinforces this with her own experience of tickets describing 'network failure' where the user could still access the internet generally.

The next step is attempting to recreate the problem independently. Ethan explains that being able to reproduce the issue allows engineers to test solutions without depending on the affected user. However, he acknowledges that many problems are intermittent or environment-specific, making recreation difficult. He recommends simulating the user's environment as closely as possible, such as connecting via VPN if that is where the problem occurs.

A significant portion of the discussion focuses on discerning whether a problem is actually a network issue or an application/service issue. Ethan argues that most tickets that land on a network engineer's desk are not, in fact, network problems. He uses examples like HTTP error codes (401, 500) versus a website that never loads to illustrate how symptoms can reveal whether the problem is at the transport layer or higher up the stack. He encourages engineers to learn application-layer protocols like HTTPS to better make this determination.

The conversation then turns to tools and information sources available for troubleshooting. Ethan highlights diff reports (configuration change comparisons) as a high-value starting point, especially when problems emerge after a change window. He also advocates for AI-powered network management tools, noting that they can surface anomalies in log data far more efficiently than manual review. Holly corroborates this, sharing examples where AI dashboards identified problems like bad cables that manual review would have missed. Logs, SNMP-based network management systems, flow data (NetFlow/IPFIX), and physical observation are all discussed as complementary sources of diagnostic information.

Packet captures via tools like Wireshark or tcpdump are described as a last resort after more obvious sources of insight have been exhausted, though Ethan acknowledges their value, particularly in automated capture infrastructures triggered by network events.

The episode covers the critical discipline of changing only one thing at a time when attempting fixes, and reverting changes that don't resolve the problem. Ethan argues this practice is essential for building institutional knowledge, as it allows engineers to know precisely what fixed a problem when it recurs. He also recommends using whiteboards to step back from the details and walk through a systematic packet-flow diagram, especially under high-pressure conditions. Holly introduces the concept of 'rubber ducking' — talking through a problem out loud to another person (or even to oneself) to surface solutions organically.

The human and organizational dimensions of troubleshooting are given significant attention. Ethan discusses formal incident response structures with incident commanders, the importance of keeping managers and stakeholders informed, and the critical role of help desk staff who absorb frontline user frustration. He strongly advocates for team-based troubleshooting, arguing that collaborative environments without ego produce better outcomes. Both hosts acknowledge the emotional difficulty of troubleshooting under pressure, with Ethan sharing personal anecdotes of frustration-driven physical outbursts, ultimately advising engineers to stay calm and seek help rather than trying to be a solo hero.

The episode closes with reminders to perform root cause analysis, document findings, and make business-level recommendations for mitigating future recurrences — framing the cost of prevention against the risk of the problem happening again.