Network Packet Sniffing with Python and Scapy

Network packet sniffing is a technique used to capture and analyze network traffic. In this tutorial, we will use Scapy, a powerful Python library, to sniff packets and extract useful information.

What is Scapy?

Scapy is a Python tool that allows you to create, send, and capture network packets. It is widely used for network security analysis and penetration testing.

Installing Scapy

To install Scapy, use the following command:

    pip install scapy
	

Basic Packet Sniffing

Let's write a simple Python script to capture packets and display basic information.

    from scapy.all import sniff

    def packet_callback(packet):
        print(packet.summary())

    sniff(prn=packet_callback, count=10)
	

Filtering Packets

You can filter packets based on specific protocols, such as capturing only TCP packets.

    sniff(filter="tcp", prn=packet_callback, count=10)
	

Extracting Packet Details

We can extract details like source and destination IP addresses from captured packets.

    def packet_callback(packet):
        if packet.haslayer(IP):
            print(f"Source: {packet[IP].src} -> Destination: {packet[IP].dst}")

    sniff(filter="ip", prn=packet_callback, count=10)
	

Running the Sniffer

Execute the script with administrator privileges to capture network packets:

    sudo python sniffer.py
	

Legal and Ethical Considerations

Ensure you have permission before sniffing network traffic. Unauthorized packet sniffing can be illegal and unethical.

Conclusion

You've learned how to capture and analyze network packets using Python and Scapy. This knowledge is useful for network monitoring, troubleshooting, and security analysis.