Packet Capture – Definition and Importance

As the data keeps streaming by, sniffers capture each packet and decode them if needed showing the value of various field in the packet. The content then gets analyzed as per the specifications. The analysis helps in determining if there are unusual packets. This helps in maintaining effective data transmission.


A packet capture can be used in two ways- legitimately and illegitimately. In legitimate use, sniffing identifies the data and transmission errors to ensure an efficient network communication. However, in an illegitimate scenario, a disgruntled employee can use the data to actually ‘capture’ the company’s credit account information. Obviously, this information is not for any saintly purpose. He may use the information to transfer the company money to his own personal accounts!

Its Importance

The primary importance of packet sniffer is detection of network. A packet capture is similar to telephone wire tapping. It detects what is going through the computer networks. The main function of the software is to monitor the performance and troubleshoot the problems that may arise in a network. In addition, it can capture the traffic from different parts of the network using the software program. Sniffing data from just one part of the network may not be advantageous as being able to get the information from all different parts of the network. Using a monitoring port does this work easily. It intercepts data at different points and sends them to administrator for decoding and analysis.

Decoding of Data

Packet capture obtains data in coded format; in other words, in a digital form. It is then decoded to a format which is easily readable by humans. This information is then read by the administrator who then detects errors. He also deciphers the root cause of the error and fixes them.

Reference Device

Some packet captures in addition to capturing data, also create traffic. This later becomes a reference device which is later used as a protocol tester. The tester generates protocol correct traffic which is used for functional testing. Creating a false traffic in this manner purposely introduces errors. This helps administrators test how well the sniffers can deal with the actual error conditions.

Analyzing Network Problems

Packet sniffers have a variety of functions. However, the chief one among them is to analyze network problems. This helps to detect intrusion attempts, detect misuse of network, monitor data in momentum, debug server communications, filter suspicious content, detect and isolate exploited systems, gather network statistics, and monitor network usage. The data collected in this manner serves as primary data for network monitoring.