Network Troubleshooting: A Guide for IT Professionals

Imagine your organization’s network suddenly goes down, halting operations and causing revenue loss by the minute. While this scenario is unsettling, it goes to show why network troubleshooting skills are essential for today’s IT professionals.

The smooth operation of network infrastructure not only supports your organization’s day-to-day operations, but also safeguards against disruptions and downtime. In a time where unplanned network outages can cost mid-sized businesses an average of $1,850 and large enterprises $25,402 per minute, having a proactive plan in place to resolve issues quickly is a must. 

A variety of issues can call for network troubleshooting. In this article, we’ll share the most common problems IT teams run into and provide a basic framework for you to follow in any scenario, so you can get your business back up and running swiftly. 

We’ll explore:  

• What is troubleshooting in networking?
• Common network issues that need troubleshooting
• Network troubleshooting tools recommended by IT pros 
• Basic network troubleshooting steps 
• Best practices for troubleshooting network problems 
• How network management tools can help 

Let’s get you set up for success. 

What is network troubleshooting? 

Network troubleshooting is the systematic process of diagnosing and resolving problems within an IT network. It involves identifying the root cause of a network issue and implementing a solution to restore functionality. 

Today, 91% of organizations experience at least one network outage per quarter. In an era where we heavily rely on technology for daily business operations, downtime has the potential to cause major financial, reputational, and productivity losses. 

Take Facebook for example, which lost an estimated $90 million during a 14-hour outage in 2019. Or, there’s payment processor Square, which experienced a systems outage in 2023 that cost its small business customers thousands in lost revenue. Minimizing this damage and enhancing network reliability requires strong network troubleshooting capabilities.  

Common network problems that need troubleshooting

Network troubleshooting issues can range far and wide from minor inconveniences to major disruptions.

Some of the most common problems IT teams are up against include: 

• Network congestion, which occurs when a network is overloaded with data (or high bandwidth usage), causing slowdowns and delays in data transmission. This can result from a variety of factors, including excessive demand for network resources during peak usage times or distributed denial-of-service (DDoS) attacks that intentionally flood the network with excessive traffic.
• Faulty network configurations, which refer to incorrect or inefficient settings in network devices or software that hinder proper network operations. These configurations can range from improper IP addressing, subnet masks, and gateway settings to incorrect DNS configurations, leading to issues like network inaccessibility, slow performance, and inability to connect to external networks.
• Hardware failures, which involve the malfunctioning of physical components in the network infrastructure—such as routers, switches, or cables—disrupting network connectivity. These failures can be caused by wear and tear, manufacturing defects, or external factors like power surges and physical damage, leading to partial or complete network outages that require hardware replacement or repair.
• IP address conflicts, which arise when two devices on the same network are assigned the same IP address, leading to connection issues for the affected devices. These conflicts can prevent one or both devices from accessing network resources and the internet, and typically require manual intervention to resolve, such as renewing IP addresses or adjusting DHCP (Dynamic Host Configuration Protocol) settings.
• Network security breaches, which may involve unauthorized access or attacks on the network, compromising data integrity, confidentiality, and network availability. Breaches can occur through various means, including malware, phishing, or exploiting vulnerabilities within the network, and can have severe consequences such as data theft, service disruption, and financial loss.

These common issues give insight into the broad scope of problems IT professionals must be prepared to tackle—and having a reliable toolkit is a great place to start. 

Network troubleshooting tools recommended by IT pros 

To effectively troubleshoot network problems, IT professionals should have a variety of software and hardware tools at their disposal.

Here’s what we’re seeing industry experts recommend. 

Software tools and applications

For network diagnostics

1. Ping commands: Essential for basic connectivity tests.
2. Traceroute: Key for identifying the path data takes across the network.
3. My traceroute (MTR): Popular for its combined features of ping and traceroute.
4. Wireshark: The go-to tool for in-depth packet analysis.
5. Zenmap / Nmap: Widely used for network exploration and security auditing.
6. PingPlotter: Useful for visualizing Ping and traceroute results over time.

For network performance and monitoring 

1. iperf3: A benchmark tool for measuring network bandwidth.
2. Wireshark: For monitoring network performance issues.
3. LibreNMS: A full-featured network monitoring system that’s community-supported.
4. Tcpdump: A lightweight and versatile packet analysis tool.
5. Graylog: For monitoring and analyzing network logs for performance insights.
6. Netflow collector: For analyzing network traffic flows.

Hardware tools

Software tools and applications can be of great value when it comes to network troubleshooting, but you’ll need a few tangible hardware tools in your kit as well. 

When it comes to network maintenance and troubleshooting, you’ll want to invest in a cable tracer, which identifies and traces specific network cables in bundles or infrastructure. You may also need a crimper, which attaches connectors to cable ends—essential for customizing network cables. 

For network setup and configuration, add these tools to your kit. First, a USB to Serial connector, which connects computers to your network devices’ console ports for configuration. Next, a DB9 to RJ45, which converts DB9 serial to RJ45 connection. Lastly, a RJ45 Female to Female, which extends your Ethernet cables by connecting two RJ45 cables. These are just the basics, but you can dive deeper into our top recommendations for hardware-based SysAdmin tools. 

Free guides and resources 

In addition to these software and hardware tools, there are many free online resources that provide valuable insights and detailed steps for network troubleshooting.

Here’s a roundup of Auvik resources you may find helpful and the key takeaways from each.

1. How to Find and Fix Asymmetric Routing Issues: Explore the challenges asymmetric routing poses for stateful firewalls, and discover strategies for diagnosing and resolving related issues. 
2. Troubleshooting and Configuring Multicast Protocols: Learn troubleshooting techniques for common multicast issues and the role of PIM (Protocol Independent Multicast) and IGMP (Internet Group Membership Protocol) in facilitating multicast packet delivery.
3. How to Troubleshoot Network Connectivity Issues: Find out how to troubleshoot common network connectivity issues reported by end users, so you can streamline the issue resolution process and reduce downtime.

7 basic network troubleshooting steps

What is the first step that needs to be taken when troubleshooting a network incident?

No matter the scenario, these basic network troubleshooting steps serve as a solid framework to work within.

1. Identify the problem

Start with a comprehensive assessment by documenting the symptoms, identifying affected systems, and determining the scope and impact of your network issue. Determine whether you’re dealing with an internal or external connectivity issue by completing the following steps: 

• Check your hardware: ‘Did you try turning it off and on again?’ While it might seem painfully obvious, faulty hardware is a common source of network issues. Verify that all of your network devices, including routers, switches, and cables, are powered on and functioning correctly. 
• Use ipconfig: Use the ipconfig command on Windows to confirm that your computer has received a valid IP address from the DHCP server. An invalid IP will begin with the numbers 169 and can prevent network access.
• Do a ping test: Send a ping to both your local router and external websites to identify potential connectivity issues within your local network or to the internet. 
• Do a DNS check: Performing a DNS check will ensure your computer can resolve domain names into IP addresses. If it can’t, websites may not load. 
• Check malware protection: Ensure your virus and malware protection software is working correctly and that nothing has been flagged that may impact network performance.
• Review database logs: Examine logs from your network devices and servers for any anomalies or errors that could indicate underlying issues affecting network performance or accessibility.

2. Establish a probable cause 

Analyze the data you collected in step one to formulate theories about potential root causes. Consider recent changes, common challenges, and known vulnerabilities that could contribute to the issue. Remember not to rule out the obvious such as an unplugged cord or a power supply issue. 

3. Test the theory

Perform targeted tests to validate your theory using the tools and techniques at your disposal. For example, if your theory is that your router has gone haywire, you might try replacing it with a new one to test whether it resolves the issue. If it doesn’t, return to step two and come up with a new theory. 

4. Establish a plan of action

Based on the outcomes of your testing, outline a detailed plan to address the root cause. This plan should include steps for implementation, a breakdown of the resources required, and the potential impact on users and business operations. Make sure to communicate effectively across the business to minimize disruption to customers and staff. 

5. Implement the solution

Execute the plan, making adjustments as necessary. Monitor the implementation process to ensure that it proceeds as expected without introducing new issues.

6. Verify full-system functionality

After applying the fix, conduct thorough tests to confirm that the original issue is resolved and that there are no residual effects. This includes checking network performance and gathering user feedback.

7. Document the process

Create a detailed report of the incident, including the initial symptoms, diagnosed cause, solution implementation, and verification process. Network documentation will be helpful for future troubleshooting and preventing similar issues.

Best practices for troubleshooting network problems 

Following best practices for network troubleshooting will enhance your efficiency and effectiveness when issues arise. Here are our top recommendations: 

• Maintain detailed documentation to better understand your network’s current and historical configurations, which will help you to diagnose issues quicker. 
• Use a systematic approach to problem-solving to help methodically narrow down the cause of the problem through a process of elimination. 
• Stay current with the latest network technologies and vulnerabilities so you can proactively anticipate and mitigate potential issues. 
• Foster a culture of continuous learning on your IT team to encourage ongoing skills development and ensure you’re prepared to tackle emerging network challenges. 

How network management tools can help with troubleshooting 

Network management tools can help you prevent network issues and facilitate easier troubleshooting when they do occur. They offer real-time network monitoring, automated alerting systems, and detailed reports on network performance—all of which work to identify potential problems before they escalate. 

These tools can also streamline the troubleshooting process by providing real-time diagnostic data and actionable insights. For example, Auvik’s internet connection check can help you quickly determine whether a network issue is internal or external by tracking abnormalities in packet loss and round trip time. The quicker you can identify the issue, the less downtime and impact on your business.

Network monitoring and troubleshooting with Auvik 

Auvik’s cloud-based network monitoring and management software helps you respond to network issues in real-time, protecting your users from unnecessary downtime and lost productivity. We streamline and simplify troubleshooting to help you keep your users connected to business critical resources.

With Auvik, you can: 

• Visualize your network: Get true network visibility and control with our real-time, automatically updating maps.
• Speed up troubleshooting: Benefit from automated device documentation and config backups that keep all of your information in one place.
• Get ahead of network issues: Find peace of mind with alerts that let you know whenever something significant changes in your network. 
• Reduce on-site visits: Gain access to your networks and make command line changes without ever having to leave your desk.

Try Auvik for yourself with a free trial.

Consider yourself a master at troubleshooting 

Network troubleshooting takes technical knowledge, analytical skills, and the right tools.

Now that you have an understanding of common network issues, a list of tools to leverage for effective troubleshooting, and a consistent framework to follow, you can better prepare your organization’s network to remain robust, secure, and fully operational.