How to Read and Extract Information from a PCAP File in Go

This article explores how Go, a programming language, can be used to read and analyze PCAP files, a widely used file format for storing network traffic data captured during the packet sniffing process. Using the pcap and gopacket packages, readers will learn how to extract Ethernet and IP addresses from packets in a PCAP file, and how this knowledge can be applied to network troubleshooting, monitoring, and security.

To get started with working with PCAP files in Go, you will need to install the libpcap library, which provides a programming interface for capturing network packets. To install the library on Ubuntu or Debian-based systems, you can use the following command:

$ sudo apt update && sudo apt install libpcap-dev -y

This command will update the package list and install the libpcap-dev package, which includes the necessary header files and libraries for building applications that use libpcap.

Once you have installed the library, you can start using Go to read and analyze PCAP files. We will demonstrate how to do this in the following sections.

package main

import (
    "fmt"                   // Import the fmt package to print messages to the console.
    "log"                   // Import the log package to log errors to the console.
    "github.com/google/gopacket/pcap" // Import the pcap package to capture packets.
    "github.com/google/gopacket" // Import the gopacket package to decode packets…