If you're new to IT or networking, one of the most important tools you’ll come across is Wireshark. It's a network protocol analyzer that lets you see exactly what’s happening in your network by capturing all the data packets traveling to and from your computer or network. Think of it like a window into the network, showing you all the communication between devices.
🔍 What Does Wireshark Do?
Wireshark captures data packets moving over the network. A packet is just a small chunk of data, like an email or a website request, that gets sent across the network. Wireshark allows you to “capture” and “analyze” these packets to see what’s going wrong with your network.
In simple terms:
It listens to your network to find out where things are breaking down.
It helps you troubleshoot by showing exactly what’s happening with the data being sent and received.
⚡ Why Should You Use Wireshark as a Beginner?
As an IT professional (even at the start of your career), Wireshark helps you by:
🚀 Spotting network issues – Sometimes, your internet might be slow, or a website might not be loading. Wireshark can help you find out why.
🚀 Checking if data is reaching its destination – You can see if data is successfully reaching the website you want to visit, or if something’s preventing it.
🚀 Understanding different types of data – Wireshark breaks down the data so you can learn more about how websites, apps, and devices communicate.
Example: If a website isn’t loading:
You might think it’s the website’s fault, but it could actually be a problem with your DNS server or a slow connection.
Wireshark will let you see exactly where the delay is happening, so you can fix it faster.
🛠️ Wireshark Basics: Getting Started
Let’s go through some basic steps to start using Wireshark.
- Capture Network Traffic Step 1: Open Wireshark and choose your network interface (the connection that’s being used, like Ethernet or Wi-Fi). Step 2: Hit the Start button to begin capturing packets. This will show everything going in and out of your computer.
- Filter Traffic Wireshark captures a lot of data, so it’s helpful to filter it and focus on what matters.
dns – Shows all DNS requests, which are made when you visit a website. If there’s a DNS issue, you’ll see it here.
http – Shows all web traffic, such as when you browse a website.
ip.addr == 8.8.8.8 – Focuses on traffic going to Google’s DNS server (8.8.8.8). This can help you check if DNS is working properly.
Why filters help:
Filters narrow down the huge amount of data Wireshark captures, making it easier to spot problems.
- Follow a TCP Stream A TCP stream is like a conversation between two devices. If you're looking at a packet and you want to see the entire back-and-forth communication, you can right-click on it and select "Follow TCP Stream". This will show you the entire exchange of data between your computer and the server, which helps you understand what went wrong.
🔥 How Wireshark Helps You Troubleshoot Network Problems
Here’s how you can use Wireshark to identify common network issues:
🚀 1. Slow Internet?
Problem: Websites load slowly, or your internet connection seems slow.
How Wireshark helps: You can see if packets are being delayed or dropped, which is a common cause of slowness.
🚀 2. DNS Issues?
Problem: You can’t reach certain websites.
How Wireshark helps: DNS packets will show if your system is having trouble resolving domain names (turning google.com into the right IP address).
🚀 3. Website Not Loading?
Problem: A website doesn’t load at all, or it takes forever.
How Wireshark helps: You can see if the website is responding to your request or if something is blocking it, like a firewall or broken server.
🚀 4. VoIP/Call Quality Issues?
Problem: VoIP calls (like Skype, Teams, Zoom) are dropping or have poor quality.
How Wireshark helps: You can analyze SIP and RTP traffic, which is used for voice calls, to see if there’s packet loss or delay.
🎯 Why Wireshark is Important for IT Support Beginners
As an IT professional, you’ll face a lot of network-related problems. Using Wireshark can help you understand the root cause of the issue and fix it faster, instead of guessing what’s wrong.
For example, if someone can’t access a website, you can use Wireshark to quickly check:
Is it a DNS issue? (Check if DNS queries are failing)
Is it a network problem? (Look for packet loss or delays)
Scenario:
Your colleague is complaining that a specific website is taking too long to load. They are connected to the company’s network, but the site seems slow only for them, not others. Here’s how you can troubleshoot this using Wireshark:
Step 1: Capture Network Traffic
Open Wireshark on your computer and select the network interface (Wi-Fi or Ethernet) that is used to connect to the internet.
Start capturing packets by clicking on the Start button.
Step 2: Filter for HTTP Traffic
In Wireshark, you’ll be capturing a lot of different types of traffic. To make it easier to find the problem, use a filter to focus on web traffic.
Type http in the filter bar. This will only show HTTP packets, which are used when loading websites.
Step 3: Browse the Website
Ask your colleague to try loading the slow website while you continue capturing traffic in Wireshark.
Wireshark will capture every data packet that’s sent when your colleague’s browser makes requests to the website.
Step 4: Analyze the Packets
Once the website has been loaded (or failed to load), stop the capture in Wireshark.
Look for requests made to the website's domain (for example, www.example.com). You'll see packets like GET requests from the browser to the web server.
Step 5: Check for Delays or Errors
Look for any time gaps between the packets. Large time gaps can indicate delays in loading resources from the website.
Check for retransmissions or timeouts (Wireshark marks these in red or black). Retransmissions often mean packets were lost and had to be resent, which can cause delays.
Look for DNS issues—If the DNS query is taking too long, it could be a reason for the slow website load.
Step 6: Use Follow TCP Stream
If you see a lot of data related to the website (for example, many packets being sent), right-click on one of the packets and choose "Follow TCP Stream". This will show you the entire conversation between the browser and the server.
This helps you identify where the issue might lie. If the server is slow to respond, that’s the problem. If there’s an issue in the data transfer, it might be a network issue.
Step 7: Check DNS Resolution
If the site is loading slowly at the beginning, it could be due to slow DNS resolution (finding the IP address of the website).
To check if DNS is the problem, you can add a DNS filter:
Type dns in the filter bar.
Look at the DNS query and response times. If the DNS server is taking longer than expected to resolve the domain, that’s likely the cause of the delay.
Step 8: Conclusion & Fix
Based on your findings, you can take the next steps:
If DNS is slow: Check the DNS settings on the device and switch to a faster DNS server like Google DNS (8.8.8.8) or Cloudflare DNS (1.1.1.1).
If the website server is slow: Contact the website’s hosting provider or investigate the server-side performance.
If there are network issues (such as packet loss): Check the local network (Wi-Fi router, cables, etc.) or escalate to the network team.
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