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What is a Packet Sniffer and How is it Used?
Staff Writer

The term packet sniffer might sound a little fishy and suspicious, but it isn’t anything like that. In network management, packet sniffing plays a very crucial role. Network managers and technicians use packet sniffers, also called packet analyzers, to diagnose underlying problems in their networks. So, a packet sniffer is essentially a tool that aids in monitoring network traffic and troubleshooting a network. It works by capturing and analyzing packets of data that flow through a particular network.

So, what does a packet sniffer look like? Well, in some cases, a packet sniffer might be in the form of a dedicated hardware device. Such a device can be easily built with embedded systems development tools. However, you can also find packet sniffers in the form of a software application. These software applications run on standard general-purpose computers performing packet sniffing tasks by using the hardware capabilities of the network.

How Do Packet Sniffers Work?

To understand how to use packet analyzers and how they work, you need to first understand that data travels through a network in the form of packets. In packet-switched networks, the data to be transmitted is broken down into several packets. These packets are reassembled once all the data packets reach their intended destination.

When a packet sniffer is installed in the network, the sniffer intercepts the network traffic and captures the raw data packets. Subsequently, the captured data packet is analyzed by the packet sniffing software and presented to the network manager/technician in a user-friendly format. By user-friendly, we mean the Network Administrator should be able to make sense of it.

Implementations and Capabilities of Packet Sniffers

It’s easy to see why packet sniffers are an indispensable tool in a network administrator’s toolkit. So, let us delve deeper into the capabilities of a sniffer and how it is used to troubleshoot and rectify network-related problems.

Monitoring network usage – Packet sniffers are great at monitoring the network usage at any given time, helping Network Managers identify whether a particular network is normal or congested. Also, making it possible to identify bottlenecks within the network and identify and improve the performance with infrastructure upgrades. Identifying problems – As mentioned earlier, packet sniffers can identify network-related issues. This is possible because a packet sniffer can analyze the conversation between two or more nodes in a network. So, in the event of a network error, the information captured by the packet sniffer can be used to identify the erroneous packets and pinpoint the node that failed to answer the request(s). Making it easy to identify faulty devices within the network in an efficient manner and providing the ability to take swift corrective actions. Detecting security loopholes – A disturbing fact about packet sniffers is their ability to work as spying tools. They also help the good guys, such as your Network Manager, by testing the vulnerabilities of a network. Once these vulnerabilities are detected, it is easier to remove the loopholes thus preventing the possibilities of hacking attempts.

Types of Packet Sniffing

IP sniffing and MAC sniffing are some of the most common ways to analyze and examine the traffic flowing through a network. Both IP and MAC sniffing rely on using the Network card for sniffing data packets that correspond to a specific IP or MAC address, respectively. Thus the network administrator can easily analyze the information packets to detect any flaws within the network.

While Packet sniffers have legitimate uses in monitoring and troubleshooting a network, they have also been widely used by hackers for gaining unauthorized access to a network and stealing information. That is why it is very important for network managers to put security measures, such as firewalls, in place to prevent intrusion to the network.

What’s the difference between a Packet Sniffer and a Protocol Analyzer?

A protocol analyzer captures and analyzes signals and data traffic over a communication channel (not a network). A communication channel can vary from on board communication to a satellite link.

Total Phase Offers a Variety of Protocol Analyzers:


CAN Protocol

I2C Protocol

eSPI Protocol

SPI Protocol

USB Protocol

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