Standard Definition
Packet capture is a networking practice involving the interception of data packets travelling over a network. Once the packets are captured, they can be stored by IT teams for further analysis. This captured data is the Packet Capture logs [source]
Simplified Analogy
Packet capture is the process of intercepting and recording data as they are sent to and fro in the network, much like capturing short clips from the screens of a traffic control centre. In Traffic Control centres, vehicles’ movements are observed as they journey to various city destinations. This observation is crucial for maintaining traffic flow and can be key in solving or preventing crimes. In a similar fashion, packet capture logs give a detailed view of data movement across the network. Reviewing these logs can offer significant insights into network activities and can be a vital tool in preventing or addressing cybercrimes. Pcaps, as they’re commonly referred to, provide a clear record of network interactions, making them essential when needing to verify or contest claims about digital exchanges. As they specifically note the source and destination of every packet, it can be used to confirm involvement of parties in any digital conversation.
Packet capture should be performed with complete authorization, especially when the network isn’t owned or managed by the capturing entity as the process has the potential to capture sensitive network-transmitted information, including personal data and passwords.