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What Is a Packet Sniffer?

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What is a packet sniffer? A packet sniffer is a piece of software or hardware that captures and analyzes data packets as they travel across a network. They are used for troubleshooting, security analysis, and network monitoring. Packet sniffers are used by network administrators, network engineers, and security analysts to see what is happening on a network.

But packet sniffers, when used maliciously by hackers, are among the top security risks associated with public Wi-Fi. In this blog post, we will look at how a packet sniffer works, what its different types and popular tools are, and how to protect against hackers using packet sniffers.

What is a packet sniffer?

A packet sniffer – also known as a packet analyzer, protocol analyzer, or network analyzer – is a piece of hardware or software used to capture and analyze data packets as they travel across a network. Packet sniffers are used for a variety of purposes, such as troubleshooting, security analysis, and network monitoring. They are also used by hackers to steal sensitive information, such as passwords an credit card numbers.

How does packet sniffer work?

When a user sends an email or downloads a file, that email or file gets broken down into parts of a certain size, or “packets.” Each packet includes information about where it came from, where it’s going, and what kind of data is inside.

A packet sniffer can intercept and log these packets as they travel across the network. By analyzing the packet data, a packet sniffer can provide valuable information about what is happening on a network.

For example, network administrators use packet sniffers to monitor network traffic for signs of trouble, such as denial-of-service attacks. packet sniffers can also be used to detect and troubleshoot problems with network hardware or software.

Hackers can use packet sniffers to intercept sensitive information, such as passwords and credit card numbers.

What are the main types of packet sniffers?

There are two main types of packet sniffers: hardware and software.

Hardware packet sniffers

Hardware packet sniffers are stand-alone devices that are connected to a network. They come with their software for analyzing packet data. Examples of hardware packet sniffers are WildPackets OmniPeek, Fluke Networks OptiView XG, and SolarWinds Network Performance Monitor.

Software packet sniffers

Software packet sniffers, on the other hand, are installed on computers or servers that are already connected to a network. They typically use the resources of the host computer to capture and analyze packet data. Examples of software packet sniffers are Wireshark, packetTotal, and NetworkMiner.

What are popular packet sniffer tools?

Among the most popular packet sniffer tools used are the following:


Wireshark can be used in both sniffing and filtering modes, with filters limiting what information you want to be captured, or letting it collect everything without limits based on your specifications. However, Wireshark can only collect data on a server with a desktop installed.


Tcpdump captures all traffic on the specified network via libcap, and then “dumps” it directly onto your screen. From that point, you can leverage the tool’s filtering capabilities to narrow down the data and display only what is relevant. Tcpdump can be used on servers without a desktop installed.

ManageEngine NetFlow Analyzer

ManageEngine NetFlow Analyzer is a comprehensive traffic analysis application that leverages flow technologies, providing you with in-depth insights into network bandwidth performance and traffic patterns. The tool uses packet sniffing to collect data and then analyzes it to provide you with detailed reports.

SolarWinds Packet Analyzer

SolarWinds Packet Analyzer is a multi-layered tool that provides a comprehensive view of your network, allowing you to detect, diagnose, and resolve network performance issues and avoid downtime. Moreover, the system uses minimal bandwidth, thereby requiring low overhead on Orion Platform servers and nodes.

Microsoft Network Monitor

The Microsoft Network Monitor is a packet sniffer that comes as a free download from the Microsoft website. It is a tool for capturing, viewing, and analyzing network traffic. Network Monitor can be used to troubleshoot and resolve problems with network hardware or software.

How to protect against hackers using packet sniffers?

Malicious hackers use packet sniffers to eavesdrop on network traffic and steal sensitive information, such as passwords and credit card numbers. Open public Wi-Fi networks are especially vulnerable to packet sniffing attacks. To protect your networks against packet sniffers, you can use the following measures:

Use encryption

Encrypting your data will make it more difficult for hackers to read and intercept your information. To encrypt your data, you can use different encryption methods, such as Secure Sockets Layer (SSL) or Transport Layer Security (TLS).

Use a VPN

A VPN encrypts your data and prevents packet sniffers from seeing what you are doing online. When you use a VPN, your data is sent through a secure tunnel, making it more difficult for packet sniffers to intercept your information.

Use a firewall

A firewall can block packet sniffers from getting onto your network in the first place. A firewall not only allows to whitelist IP addresses but also to block specific ports that packet sniffers use to get onto your network.

Wrapping up

Many cyberattacks start with packet sniffing. By understanding what packet sniffers are and how they work, you can take measures to protect your networks against them. But those defensive measures work best when they’re part of a more holistic approach to cybersecurity, namely with the regular testing of your network security, application security, and cloud security.

With the growing rate of automated cyberattacks, many organizations have included an annual or bi-annual penetration test of their systems as an essential component of their cybersecurity strategy.

Contact us if you need help with your penetration testing project.

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