Wireshark ( Protocol Analyser ) Troubleshooting in detail..

 

1. Pinpoint Network Bottlenecks

Have you ever felt like your internet is slower than it should be? Wireshark can help you find the culprit.

Wireshark can monitor traffic in the background and then produce charts or graphs so you can get a visual representation of what is happening and when.

• How: Capture traffic while performing a network-intensive task (like downloading a large file). Use the “Statistics” > “Conversations” menu to see which connections are using the most bandwidth. Look for unusually high latency or packet loss, which could indicate a bottleneck. You can also use the “IO Graphs” tool to visualize network traffic patterns over time.

2. Diagnose a Faulty Network Card (NIC)

Do you suspect your network card is malfunctioning? Wireshark can provide clues.

Often, a network card or interface doesn't just fail. It starts to malfunction, often causing substantial network issues including broadcasts requiring a response from all devices on the same subnet.

• How: Capture traffic on your machine. Look for an excessive number of CRC errors or frame check sequence errors. These indicate that your NIC might be corrupting data. You can filter for these errors using eth.crc_errors != 0 or frame.check_seq_error.

3. Optimize Work Schedules by Analyzing Network Traffic

Do you need to schedule maintenance or updates during off-peak hours? Wireshark can help you find the quietest times on your network.

If your network experiences peak loads during certain times, such as early morning or post-lunch login, you can use this information to determine better shift patterns.

• How: Capture network traffic over a typical workday or week. Use the “Statistics” > “IO Graphs” tool to visualize traffic patterns. Look for periods with consistently low activity.

4. Detect and Analyze Hacking Attempts

Wireshark can be your first line of defense against malicious activity.

This is covered in more detail in our hacking and penetration testing courses but Wireshark is an often forgotten tool in your network hardening strategy.

• How: Look for unusual patterns like port scans (many connection attempts to different ports on your machine), suspicious login attempts (failed authentication requests), or known attack signatures. Use display filters to isolate specific types of traffic (e.g., tcp.port == 80 for HTTP traffic, tcp.flags.syn == 1 and tcp.flags.ack == 0 for SYN scans).

5. Troubleshoot VoIP Call Quality Issues

Choppy audio or dropped calls? Wireshark can help you diagnose VoIP problems.

While some protocols can tolerate packet loss, voice calls cannot. This is why it's so important to be able to determine what is happening behind the scenes.

• How: Capture traffic during a VoIP call. Analyze the RTP (Real-time Transport Protocol) streams for packet loss, jitter (variation in packet arrival times), and high latency. These can all contribute to poor call quality. Use filters like rtp or sip to focus on VoIP traffic.

6. Identify Bandwidth Hogs on Your Network

Is someone on your network consuming an unfair share of bandwidth? Wireshark can help you identify them.

While many companies have acceptable use policies, others let employees do pretty much whatever they want during work time on work devices. I've seen it myself and the impact it can have on everyone else trying to work.

• How: Capture network traffic and use the “Statistics” > “Conversations” menu to see which IP addresses or applications are using the most bandwidth. You can also use the “Endpoints” menu to see a list of all devices communicating on the network.

7. Verify Network Segmentation

Want to make sure your network is properly segmented for security? Wireshark can help.

While setting up VLANs is pretty simple, you may well want to have policies in place to hide some of them and only allow certain VLANs to communicate with others.

• How: Capture traffic on different segments of your network. Analyze the traffic to ensure that devices in one segment are not communicating with devices in another segment unless explicitly allowed.

8. Debug Network Application Issues

Have problems with a specific application? Wireshark can help you see what's happening behind the scenes.

This especially helps because you can dig into the packet, frame, and bits on the wire. I recommend this method for passing any IT exam so you understand what is happening.

• How: Capture traffic while using the application. Analyze the application and server communication to identify any errors or unexpected behavior. Filter by the application's port number or protocol (e.g., http for web traffic, dns for DNS lookups).

9. Learn About Network Protocols

Want to get a deeper understanding of how network protocols work? Wireshark is an excellent learning tool.

• How: Capture traffic and explore the detailed information provided for each packet. You can see the headers, payload, and other details for protocols like TCP, IP, HTTP, DNS, and many more.

10. Test Network Security Configurations

Want to test the effectiveness of your firewall or intrusion detection system?

• How: Simulate different types of attacks (e.g., port scans, denial-of-service attacks) and use Wireshark to capture and analyze the traffic. This can help you identify any weaknesses in your security configuration.