24 May 2024

How network troubleshooting made easy IT system (Image by OCTOBITS)

Octobits Blog – Network troubleshooting is the systematic process of diagnosing and resolving issues within a computer network.

As our reliance on networks continues to escalate, so does the complexity of the networks. Network problems are a universal frustration felt by individuals and businesses alike.

Network issues, whether they stem from hardware failures, software glitches, configuration errors, or overloaded systems, have the potential to disrupt the smooth operation of businesses.

These problems can manifest as data center security issues, slow performance, security breaches, or outright hardware failure, each with unique challenges and implications.

Let’s say you have network changes, even well-intentioned ones, which could inadvertently introduce security holes into the data center.

Troubleshooting skills are needed to verify that each change has kept the security posture strong.

To understand how data center security gets attacked, readHow Solid Are Your Data Center Security Fundamentals? A Complete Guide.’

The ability to limit such interruptions through ongoing and accurate network monitoring is a testament to the power of proactive and preventative troubleshooting efforts.

These efforts enhance productivity, reduce downtime, and significantly improve employee and customer satisfaction​​.

In this guide, we’ll navigate the world of network troubleshooting. Let’s start.

What Is Network Troubleshooting?

Network troubleshooting employs a structured approach, combining diagnostic tools and problem-solving methodologies to identify issues that disrupt network health.

Effective troubleshooting requires a deep understanding of how various network technologies interact.

So, network troubleshooting goes beyond simply reacting to problems. It’s a proactive discipline focused on identifying and resolving underlying issues within the intricate system of a computer network.

Troubleshooting experts combine methodical analysis with a deep understanding of how various network components communicate.

You’ll need to gather clues, analyze evidence, and apply your knowledge of networking principles to eliminate suspects’ potential causes one by one. 

It’s about exercising both your logical and creative sides. So, you need to utilize a mix of diagnostic techniques, tools, problem-solving skills, and knowledge of networking technologies.

Using commands such as ping and tracert (or traceroute on Unix/Linux systems) allows technicians to test the reachability of devices within the network and to trace the path data takes to reach its destination.

A DNS check, using the nslookup command, further aids in identifying issues related to domain name resolution, which can be a common source of network troubles. 

Tools like ipconfig on Windows systems can help assess the network configuration and identify if devices obtain valid IP addresses or necessitate a renewal of their IP lease​.

The process also involves monitoring for viruses and malware, which can severely impact network performance and security.

Troubleshooting can get more complex in specialized networking scenarios, such as those involving Border Gateway Protocol (BGP).

Issues like incorrect route advertisements or the need for multi-hop configurations to establish neighborship with non-directly connected eBGP peers are examples.

BGP monitoring tools can provide invaluable insights into BGP session health and route advertisements, facilitating the identification and resolution of issues before they escalate​.

Tools like SolarWinds Network Performance Monitor (NPM) offer advanced features for network baseline establishment, alert customization, and performance metrics comparison, facilitating faster root cause analysis and resolution​.

Common Network Issues

Before anyone starts troubleshooting, it’s crucial to realize what types of problems they might face.

This helps narrow the focus and gives direction to the troubleshooting process.

Addressing Slow Connectivity and Intermittent Drops

Slow connectivity often results from bandwidth limitations or network congestion.

A comprehensive bandwidth utilization analysis can determine whether a bandwidth upgrade is necessary. Tools like Wireshark or ntopng can assist in this analysis​.

For intermittent connection drops, examining hardware components for faults using diagnostics tools like ethtool or mii-tool on Linux platforms can reveal link-level issues. 

Resolving DNS Issues

DNS problems, which involve difficulties in resolving domain names to their corresponding IP addresses, can be diagnosed using commands like dig and nslookup.

These commands allow you to query DNS servers for domain-related information and identify potential resolution failures.

For instance, nslookup can test whether the client or server-level DNS settings are causing issues.

Mitigating Hardware Malfunctions and Security Concerns

Hardware issues, such as faulty cables, routers, or switches, can lead to network problems.

These issues are often identified through physical inspections or monitoring tools that detect device malfunctions.

Regular hardware inspections and employing SNMP-based monitoring tools like Nagios or Zabbix can help detect and address these problems before they escalate​​.

On the security front, implementing strong encryption standards through IPsec or SSL/TLS and conducting regular security audits using tools like Wireshark and Nessus can bolster network security and mitigate vulnerabilities​ (NinjaOne)​.

What are the 5 Types of Troubleshooting?

The right troubleshooting approach depends on several factors – the problem, how complex the network is, and the experience of the troubleshooter.

Yes, there’s no one-size-fits-all method. But, 5 methods and strategies are commonly used in the troubleshooting process.

The first is bottom-up troubleshooting. This type involves starting with the physical layer.

This type ensures all hardware components, like cables and routers, function correctly before moving up through the network layers.

This approach is often practical for issues rooted in hardware malfunctions or physical connectivity problems.

On the other hand, we have top-down troubleshooting as the second layer.

This approach begins at the application layer, examining software configurations and application behaviors before proceeding to lower layers.

This method is suited for issues related to software malfunctions or misconfigurations at the higher levels of the network stack.

Now, we have a divide-and-conquer troubleshooting approach. This type splits the problem area in half to isolate the issue more efficiently.

Suppose a ping test from the network layer is successful. In that case, lower layers are functioning, and the problem might reside in the upper layers.

This approach is highly effective when the origin layer of the issue is unclear, providing a balanced strategy between the bottom-up and top-down methods​​.

Next, we can see the path. Like its name, this type involves tracing the data’s journey through the network to identify where the fault occurs.

This method reduces the scope of troubleshooting to only the links and devices involved in the data’s path, making it easier to pinpoint the exact location of the problem.

Lastly, we have comparison troubleshooting. Comparison relies on having a known working network configuration or setup as a reference point.

Discrepancies can be highlighted by comparing the working setup with the current broken one, directing the troubleshooter toward the culprit.

This approach shines when recent network changes may have unintentionally triggered the problem. And change control is also essential for the company.

Kindly read Change Control Guideline: The Secret to Stress-Free IT Updates to understand how change control brings holes in your security.

Troubleshooting Method

A methodical approach to troubleshooting involves several steps, starting from the identification of the problem to the implementation of a solution.

This section will explore the recommended troubleshooting method, enriched with examples and best practices.

Understanding the Network Environment

The process begins with a thorough understanding of the network environment.

This means getting acquainted with the network’s hardware and software components, which is foundational for effective problem-solving​.

How is the network physically and logically laid out? What routers, switches, firewalls, and other devices are in use? What operating systems, network management tools, and critical applications?

Identifying the Problem

The problems could range from connectivity disruptions and slow network performance to access issues concerning specific services.

Establishing a theory of probable cause is a critical next step in troubleshooting.

You hypothesize based on the observed symptoms and an in-depth understanding of the network.

This hypothesis aims to identify the root cause of the issue at hand.

This stage often leans on both experience and theoretical knowledge​. You need to answer the following: Is it one user, a whole department, or the entire site?

Or is connectivity loss, slow speeds, or specific application failures? Or have there been any recent updates or new devices added?

Establishing a Theory of Probable Cause

As you know, “No internet access at all” commonly suggests router failure or an issue with the internet provider.

Or “Slow speeds to specific websites” could be DNS problems or routing issues farther out on the internet.

For this, various network troubleshooting tools and commands come into play.

Commands such as ipconfig, ping, tracert (or traceroute), and nslookup are indispensable for diagnosing various network problems.

For instance, ipconfig can display the TCP/IP network configuration settings, allowing you to verify if they are correct.

Meanwhile, ping tests connectivity with a remote device and traces the route to a destination, providing insights into where connectivity might fail​.

Establishing a Plan of Action

Once the cause is identified, it’s time to establish a plan of action.

This might involve reconfiguring network devices, updating software, or replacing faulty hardware.

Implementing the solution carefully while monitoring the network’s response is essential.

This phase might require collaboration with other IT professionals to ensure a comprehensive approach​.

Implementing the Solution

The final step is verification and monitoring. After applying a fix, it’s essential to confirm the issue is resolved and watch for any recurrence.

But carefully, one change at a time helps isolate what works or doesn’t. This ensures that the solution is not just a temporary patch but a sustainable fix to the problem​.

Note what you changed in case the issue recurs or the fix has unexpected side effects.


Network troubleshooting is an ongoing skill essential for keeping IT systems reliable.

While it can sometimes seem daunting, a structured approach, understanding various troubleshooting types, and the right tools will make all the difference.

Remember, patience and clear thinking are your greatest allies in network troubleshooting.

Now, it’s time for your company’s network troubleshooting to become robust, secure, and capable of supporting the demands of the modern digital landscape.