Python Thread-Based Network Sniffing with Scapy

Network sniffing is a foundational technique in the fields of network security, performance monitoring, and troubleshooting. By capturing and analyzing network packets, professionals gain visibility into traffic patterns, detect anomalies, and investigate potential threats. Python, with its rich ecosystem of libraries, offers powerful tools to build custom sniffing solutions. Among these tools, Scapy stands out as a versatile library designed specifically for packet manipulation and analysis.

This article will provide a comprehensive introduction to network sniffing, explain the role and capabilities of Scapy, and discuss the benefits of incorporating threading into sniffing applications. By the end, you will understand the core concepts needed to create efficient packet sniffers in Python.

Understanding Network Sniffing

Network sniffing refers to the process of intercepting and logging traffic that passes over a digital network. This practice is essential in many areas:

  • Security Analysis: Detecting intrusions, malware communication, and data exfiltration.

  • Network Troubleshooting: Identifying bottlenecks, misconfigurations, and dropped packets.

  • Protocol Development: Understanding and debugging new or custom protocols.

  • Performance Monitoring: Tracking latency, throughput, and error rates.

A network sniffer captures packets at various layers of the OSI model, typically focusing on Layer 2 (Data Link) or Layer 3 (Network) to capture Ethernet frames or IP packets, respectively.

Traditional sniffing tools like Wireshark provide graphical interfaces for packet capture and analysis. However, automated or programmatic sniffing is often necessary for real-time monitoring, automated alerts, or integrating sniffing into broader systems. This is where Python and Scapy come into play.

Introducing Scapy: A Pythonic Packet Manipulation Tool

Scapy is an open-source Python library that enables users to craft, send, capture, and manipulate network packets. Unlike other packet capture libraries that mainly capture and display traffic, Scapy allows full interaction with packets at multiple protocol layers.

Key Features of Scapy

  • Packet Crafting: Create packets from scratch for testing and penetration testing.

  • Protocol Support: Supports many protocols, including Ethernet, IP, TCP, UDP, ICMP, and custom protocols.

  • Sniffing: Capture live packets with detailed parsing.

  • Injection: Send packets to the network to test devices or protocols.

  • Extensibility: Easily extendable to support new protocols or features.

Installing Scapy

To start using Scapy, installation is straightforward using pip:

bash

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pip install scapy

 

Some operating systems may require additional dependencies or running the script with elevated privileges to access network interfaces.

Basic Scapy Usage for Sniffing

A simple way to sniff packets with Scapy is to use the sniff() function:

python

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from scapy.all import sniff

 

def packet_callback(packet):

    print(packet.summary())

 

sniff(prn=packet_callback, count=10)

 

This script captures ten packets and prints a summary of each. The prn parameter takes a callback function executed for every captured packet.

While this example is useful, it runs synchronously and blocks the main program until it captures the specified number of packets. For more advanced scenarios like continuous sniffing or integrating with other tasks, threading is a better approach.

Why Use Threading for Network Sniffing?

Threading allows multiple parts of a program to run concurrently, improving efficiency and responsiveness. In network sniffing, threading is valuable for several reasons:

  • Non-blocking Operation: The sniffing process runs independently of the main application logic, avoiding freezes.

  • Real-Time Processing: Packet capture and analysis can happen simultaneously.

  • Resource Management: Allows distributing tasks such as logging, analysis, or alerting to different threads.

  • Multiple Interfaces or Filters: Separate threads can sniff on different interfaces or with different filters concurrently.

Python provides the threading module, which is simple to use for starting and managing threads. Combining Scapy with Python threading creates flexible sniffers suitable for real-time network monitoring tools or automated network analysis systems.

Python Threading Basics

A thread is a lightweight subprocess that runs in parallel with other threads within a single process. Here is a simple example of running a function in a separate thread:

python

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import threading

 

def background_task():

    print(“Task running in background”)

 

thread = threading.Thread(target=background_task)

thread.start()

 

print(“Main program continues”)

 

The Thread object takes a target function and runs it independently when start() is called. The main program continues execution without waiting for the thread unless join() is used.

Using threading in sniffing scripts allows continuous packet capture without stopping the rest of the program. This approach is essential in applications requiring both packet capture and real-time user interaction or data processing.

Setting Up a Simple Threaded Sniffer with Scapy

Before diving into advanced sniffing techniques, it is helpful to see how threading integrates with Scapy in a simple example.

python

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from scapy.all import sniff

import threading

 

def sniff_packets():

    sniff(prn=lambda x: x.summary(), count=10)

 

sniff_thread = threading.Thread(target=sniff_packets)

sniff_thread.start()

 

print(“Sniffing started in a separate thread”)

 

In this script:

  • The sniff_packets function calls Scapy’s sniff() to capture 10 packets and print summaries.

  • A thread is created to run sniff_packets without blocking the main thread.

  • The main program immediately prints a message and can continue executing other tasks.

This simple example demonstrates how threading helps maintain responsiveness and modularity.

Challenges in Threaded Sniffing

Despite the advantages, threaded sniffing comes with challenges:

  • Thread Safety: Scapy functions may not be inherently thread-safe. Care must be taken when accessing shared data structures.

  • Resource Conflicts: Multiple threads sniffing the same interface may cause packet duplication or loss.

  • Data Synchronization: Passing captured packets safely between threads requires synchronization mechanisms like thread-safe queues.

  • Performance Overhead: Threads consume resources, and improper management can degrade performance.

Understanding these challenges is crucial for building robust sniffers that operate reliably under heavy traffic or in complex environments.

With a solid understanding of network sniffing fundamentals, Scapy’s capabilities, and Python threading basics, you are ready to start building practical threaded sniffing tools.

The next article in this series will focus on constructing a complete threaded packet sniffer with Scapy, including filtering, callback handling, and basic packet processing. You will learn how to manage threads properly, use packet filters for efficiency, and test your sniffer on live networks.

Building a Threaded Packet Sniffer Using Scapy

In the first part, we introduced the concept of network sniffing, explored Scapy’s capabilities, and discussed the importance of threading for creating responsive sniffing tools. This article will walk you through building a functional threaded packet sniffer in Python using Scapy.

You will learn how to:

  • Utilize Python’s threading module to run sniffing asynchronously

  • Filter captured packets efficiently with Berkeley Packet Filter (BPF) syntax.

  • Handle packets with custom callback functions inside the thread.s

  • Test the sniffer and interpret the output.

By the end of this article, you will have a reusable, thread-based packet sniffer foundation to expand for various network monitoring tasks.

Recap of Key Concepts

  • Sniffing captures network packets from interfaces for analysis.

  • Threading allows running sniffing tasks independently without blocking the main program.

  • Scapy provides packet capturing, decoding, and crafting functionalities.

  • BPF filters enable filtering traffic at the kernel level to reduce unnecessary packets.

Setting Up the Threaded Packet Sniffer

Let’s begin by writing a Python script that starts a sniffing thread to capture packets without freezing the main program. This example will include basic filtering and packet summary printing.

Step 1: Import Required Libraries

We need Scapy for sniffing and threading to create the sniffing thread.

python

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from scapy.all import sniff

import threading

 

Step 2: Define the Packet Handler Function

This function will be called every time a packet is captured. You can customize this function to analyze, log, or respond to packets.

python

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def packet_handler(packet):

    print(packet.summary())

 

Step 3: Define the Sniffing Function

This function wraps Scapy’s sniff() and runs indefinitely (until stopped) to capture packets matching a filter.

python

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def sniff_packets(interface=None, filter=None, count=0):

    sniff(iface=interface, filter=filter, prn=packet_handler, count=count)

 

  • iface specifies the network interface to listen on. The default listens on all.

  • Filter is a BPF filter string, e.g., “tcp” or “port 80”.

  • Count is how many packets to capture; zero means unlimited.

Step 4: Create and Start the Sniffing Thread

Now we create a thread that runs the sniff_packets function and start it.

python

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def start_sniffing_thread(interface=None, filter=None, count=0):

    sniff_thread = threading.Thread(target=sniff_packets, args=(interface, filter, count))

    sniff_thread.daemon = True  # Allow program to exit even if thread is running

    sniff_thread.start()

    return sniff_thread

 

Using daemon=True means the thread won’t block the program’s exit.

Step 5: Main Program Execution

The main program can start the sniffer thread and continue other tasks.

python

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if __name__ == “__main__”:

    interface = “eth0”  # Change to your network interface

    bpf_filter = “tcp port 80”  # Filter HTTP traffic only

    print(f”Starting sniffer on {interface} with filter ‘{bpf_filter}'”)

 

    thread = start_sniffing_thread(interface, bpf_filter)

 

    Try:

        While True:

            # Main program can do other things here

            pass

    Except KeyboardInterrupt:

        print(“\nStopping sniffer.”)

 

Explanation:

  • The sniffer runs in a background thread.

  • The main thread stays alive to keep the program running.

  • Pressing Ctrl+C stops the program.

Testing Your Threaded Sniffer

Make sure you run the script with administrative or root privileges, as sniffing requires access to network interfaces. On Linux or macOS, use:

bash

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sudo python3 threaded_sniffer.py

 

If you run on Windows, launch the command prompt as Administrator.

When you browse websites or generate TCP traffic on port 80, you will see packet summaries printed continuously without blocking your console.

Customizing Packet Handling

The packet handler function is the heart of your sniffer. Instead of just printing summaries, you can extract detailed information, such as IP addresses, ports, or payload data.

Example:

python

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def packet_handler(packet):

    If packet.haslayer(“IP”):

        ip_src = packet[“IP”].src

        ip_dst = packet[“IP”].dst

        print(f”IP Packet: {ip_src} -> {ip_dst}”)

 

    if packet.haslayer(“TCP”):

        tcp_sport = packet[“TCP”].sport

        tcp_dport = packet[“TCP”].dport

        print(f”TCP Ports: {tcp_sport} -> {tcp_dport}”)

 

This prints the source and destination IPs and ports for each packet.

Using Filters to Improve Efficiency

Filters are critical in packet sniffing to reduce noise and improve performance. The Berkeley Packet Filter (BPF) syntax is widely used to specify what packets to capture.

Some useful filters:

  • “tcp” — capture only TCP packets

  • “udp” — capture only UDP packets

  • “icmp” — capture ICMP (ping) packets

  • “port 80” — capture traffic on port 80 (HTTP)

  • “host 192.168.1.1” — capture traffic to or from a specific IP

Combining filters is possible, for example: “tcp and port 443” captures HTTPS traffic.

Managing Thread Lifetime and Cleanup

Because the sniffing thread runs indefinitely by default, managing its lifecycle is important. You can modify the sniff_packets function to stop after a timeout or a certain count.

Example: sniff for 20 packets, then stop.

python

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def sniff_packets(interface=None, filter=None, count=20):

    sniff(iface=interface, filter=filter, prn=packet_handler, count=count)

 

Alternatively, you can add a timeout parameter to stop sniffing after a set number of seconds.

python

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def sniff_packets(interface=None, filter=None, timeout=30):

    sniff(iface=interface, filter=filter, prn=packet_handler, timeout=timeout)

 

Use these techniques to ensure your program doesn’t hang indefinitely.

In this article, you built a threaded packet sniffer using Scapy and Python’s threading module. Key takeaways:

  • Using threads allows your sniffing process to run without blocking other code.

  • Scapy’s sniff() function, combined with callback handlers, enables flexible packet processing.

  • Applying BPF filters optimizes sniffing performance by reducing captured packets.

  • Custom packet handlers provide the ability to analyze and react to network traffic programmatically.

  • Managing thread lifecycle and sniffing parameters like count and timeout helps maintain control over your sniffer.

This foundation prepares you for more advanced sniffing features such as real-time analysis, logging, and multi-threaded sniffing, which we will cover in the next part of this series.

Real-Time Analysis and Asynchronous Logging

In the previous parts, you learned how to create a basic threaded packet sniffer using Python and Scapy. This article will take it further by integrating real-time packet analysis and asynchronous logging, key features that make a sniffer practical for continuous monitoring and data collection.

You will learn how to:

  • Implement live analysis on captured packets inside the thread

  • Log packet details asynchronously to avoid slowing down the sniffing process.

  • Manage thread-safe queues to pass data between threads safely.y

  • Use Python’s queue and logging modules effectively.

By enhancing your sniffer with these capabilities, you create a more powerful and responsive network monitoring tool.

Why Real-Time Analysis and Asynchronous Logging?

When sniffing network traffic, you want to analyze packets as they arrive but avoid delays caused by heavy processing or file writing inside the capture callback. If packet processing takes too long, packets may be dropped.

By separating packet capture, analysis, and logging into different threads communicating via queues, you ensure smooth operation and scalable design.

Setting Up the Environment

Before starting, ensure you have:

  • Python 3.x installed

  • Scapy installed (pip install scapy)

  • Basic knowledge of threading and queue modules

Designing the Multi-Threaded Architecture

We will implement two primary threads:

  1. Sniffer Thread: Captures packets and pushes them into a thread-safe queue.

  2. Processor Thread: Consumes packets from the queue, performs analysis, and logs results asynchronously.

This separation prevents the sniffing thread from being blocked by processing delays.

Step 1: Import Required Modules

python

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from scapy.all import sniff

import threading

import queue

import logging

import time

 

Step 2: Configure Asynchronous Logging

Set up a logger that writes to a file asynchronously.

python

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logging.basicConfig(

    filename=’packets.log’,

    filemode=’a’,

    format=’%(asctime)s – %(levelname)s – %(message)s’,

    level=logging.INFO

)

Logger = logging.getLogger()

 

Step 3: Initialize a Thread-Safe Queue

This queue will hold captured packets for processing.

python

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packet_queue = queue.Queue()

 

Step 4: Modify Packet Handler to Enqueue Packets

Instead of processing directly, the sniffer thread will place packets in the queue.

python

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def packet_handler(packet):

    try:

        packet_queue.put(packet)

    Except queue.Full:

        print(“Warning: Packet queue is full, dropping packet.”)

 

This design allows the sniffing thread to run quickly.

Step 5: Define the Packet Processing Thread Function

This thread will pull packets from the queue, analyze them, and log the information.

python

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def process_packets():

    while True:

        Try:

            packet = packet_queue.get(timeout=3)

        Except queue.Empty:

            Continue # No packet to process, loop again

 

        analyze_and_log(packet)

        packet_queue.task_done()

 

Step 6: Implement Real-Time Analysis and Logging

Define a function that extracts key information from each packet and logs it.

python

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def analyze_and_log(packet):

    If packet.haslayer(“IP”):

        ip_src = packet[“IP”].src

        ip_dst = packet[“IP”].dst

        protocol = packet[“IP”].proto

 

        log_msg = f”IP Packet: {ip_src} -> {ip_dst} | Protocol: {protocol}”

 

        if packet.haslayer(“TCP”):

            tcp_sport = packet[“TCP”].sport

            tcp_dport = packet[“TCP”].dport

            log_msg += f” | TCP Ports: {tcp_sport} -> {tcp_dport}”

 

        elif packet.haslayer(“UDP”):

            udp_sport = packet[“UDP”].sport

            udp_dport = packet[“UDP”].dport

            log_msg += f” | UDP Ports: {udp_sport} -> {udp_dport}”

 

        logger.info(log_msg)

        print(log_msg)

 

This function can be extended to include payload inspection or alert generation.

Step 7: Start Sniffer and Processor Threads

Integrate everything in the main function.

python

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def sniff_packets(interface=None, filter=None, count=0):

    sniff(iface=interface, filter=filter, prn=packet_handler, count=count)

 

if __name__ == “__main__”:

    interface = “eth0”  # Update for your system

    bpf_filter = “ip”   # Capture all IP traffic

 

    # Start the processing thread

    processor_thread = threading.Thread(target=process_packets)

    processor_thread.daemon = True

    processor_thread.start()

 

    # Start sniffing in the main thread or a separate thread if preferred

    print(f”Starting packet capture on {interface} with filter ‘{bpf_filter}'”)

    try:

        sniff_packets(interface=interface, filter=bpf_filter)

    Except KeyboardInterrupt:

        print(“Exiting…”)

 

    packet_queue.join()  # Wait until all packets are processed before exit

 

Advantages of This Architecture

  • Non-blocking capture: Sniffer thread focuses solely on grabbing packets.

  • Thread-safe communication: The Queue safely passes packets between threads.

  • Scalable logging: Logging occurs independently, avoiding bottlenecks.

  • Real-time console output: You see analyzed data live while logs are stored.

Handling Packet Queue Overflow

If the packet volume exceeds the processing speed, the queue may fill up. Here are some strategies to handle this:

  • Increase the queue size with the queue.Queue(maxsize=1000) to buffer more packets.

  • Implement backpressure or dropping policies to avoid memory overflow.

  • Optimize analysis logic to speed up processing.

  • Run multiple processing threads to parallelize work.

Extending Real-Time Analysis

Beyond basic IP and TCP/UDP info, you can:

  • Detect suspicious packets (e.g., SYN floods, port scans)

  • Extract and decode payloads (HTTP headers, DNS queries)

  • Aggregate statistics (packet counts per IP, protocol breakdowns)

  • Trigger alerts or notifications on anomalies

Such enhancements transform your sniffer into a proactive network security tool.

 

In this article, you advanced your threaded Python sniffer by adding real-time analysis and asynchronous logging. This design separates packet capture and processing responsibilities, improving performance and reliability in live environments.

You now understand how to:

  • Use queues for thread-safe packet exchange

  • Configure logging to capture detailed packet info

  • Analyze packets in a separate thread without blocking sniffing

  • Manage the thread lifecycle and graceful shutdown.

The next part of this series will focus on integrating packet filtering based on custom rules and exporting captured data for offline analysis.

Advanced Filtering, Custom Handling, and Data Export

In the earlier parts of this series, you learned the fundamentals of thread-based sniffing in Python using Scapy, how to structure the code for real-time analysis, and how to implement asynchronous logging. This final part will take your sniffer to the next level by demonstrating how to apply advanced packet filtering, customize packet handling based on rules, and export the captured data for further offline processing.

Why Advanced Filtering and Data Export Matter

Networks generate vast amounts of traffic, so capturing everything indiscriminately often leads to overwhelming volumes of data, making meaningful analysis difficult. Filtering packets based on criteria such as IP addresses, protocols, ports, or payload content helps focus on relevant traffic.

Exporting data to external files or databases enables deeper analysis using specialized tools or for long-term storage and audit purposes.

Step 1: Enhancing Packet Filtering with Custom Rules

While Scapy supports Berkeley Packet Filter (BPF) expressions during sniffing, Python allows you to add a layer of filtering in your packet processing thread to implement more complex logic.

Here is how you can combine BPF filters with in-code filtering:

python

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def custom_filter(packet):

    # Example: Capture only TCP packets destined to port 80 (HTTP)

    If packet.haslayer(“TCP”) and packet[“TCP”].dport == 80:

        return True

    return False

 

Modify the packet handler to filter before queuing:

python

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def packet_handler(packet):

    if custom_filter(packet):

        try:

            packet_queue.put(packet)

        Except queue.Full:

            print(“Warning: Packet queue is full, dropping packet.”)

 

This two-level filtering lets you balance performance and precision.

Step 2: Implementing Custom Packet Handling

Based on the type of packets you are interested in, you can define different actions. For instance, if you want to detect HTTP GET requests, you can analyze the TCP payload.

python

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def analyze_and_log(packet):

    If packet.haslayer(“IP”):

        ip_src = packet[“IP”].src

        ip_dst = packet[“IP”].dst

        protocol = packet[“IP”].proto

 

        log_msg = f”IP Packet: {ip_src} -> {ip_dst} | Protocol: {protocol}”

 

        if packet.haslayer(“TCP”):

            tcp_sport = packet[“TCP”].sport

            tcp_dport = packet[“TCP”].dport

            log_msg += f” | TCP Ports: {tcp_sport} -> {tcp_dport}”

 

            # Inspect the payload for an HTTP GET request

            in the packet.haslayer(“Raw”):

                payload = packet[“Raw”].load.decode(errors=’ignore’)

                If payload.startswith(“GET”):

                    log_msg += ” | HTTP GET request detected”

                    # You could extract the requested URL or headers here

 

        logger.info(log_msg)

        print(log_msg)

 

This allows you to detect and log application-layer events, providing richer context.

Step 3: Exporting Captured Packets for Offline Analysis

Exporting packets is essential for sharing data with analysis tools like Wireshark or for archival. Scapy supports saving packets to PCAP files, which are the standard for packet data.

To save captured packets:

  1. Initialize a packet list to store packets.

python

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captured_packets = []

 

  1. Modify the packet handler or processing thread to append packets to this list.

python

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def packet_handler(packet):

    if custom_filter(packet):

        try:

            packet_queue.put(packet)

            captured_packets.append(packet)

        Except queue.Full:

            print(“Warning: Packet queue is full, dropping packet.”)

 

  1. After stopping the sniffer, save the list to a pcap file.

python

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from scapy.utils import wrpcap

 

def save_packets(filename=”captured_packets.pcap”):

    wrpcap(filename, captured_packets)

    print(f”Saved {len(captured_packets)} packets to {filename}”)

 

  1. Call save_packets() during graceful shutdown.

Step 4: Integrating Graceful Shutdown and Cleanup

Ensure that when the user interrupts the sniffing process, all packets are processed, and data is saved.

python

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import signal

import sys

 

def signal_handler(sig, frame):

    print(“Interrupt received, shutting down…”)

    packet_queue.join()

    save_packets()

    sys.exit(0)

 

signal.signal(signal.SIGINT, signal_handler)

 

This approach handles Ctrl+C interruptions cleanly.

Step 5: Full Example Incorporating All Features

python

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from scapy.all import sniff

from scapy.utils import wrpcap

import threading

import queue

import logging

import signal

import sys

 

logging.basicConfig(

    filename=’packets.log’,

    filemode=’a’,

    format=’%(asctime)s – %(levelname)s – %(message)s’,

    level=logging.INFO

)

logger = logging.getLogger()

 

packet_queue = queue.Queue(maxsize=1000)

captured_packets = []

 

def custom_filter(packet):

    If packet.haslayer(“TCP”) and packet[“TCP”].dport == 80:

        return True

    return False

 

def packet_handler(packet):

    if custom_filter(packet):

        try:

            packet_queue.put(packet)

            captured_packets.append(packet)

        Except queue.Full:

            print(“Warning: Packet queue full, dropping packet.”)

 

def analyze_and_log(packet):

    if packet.haslayer(“IP”):

        ip_src = packet[“IP”].src

        ip_dst = packet[“IP”].dst

        protocol = packet[“IP”].proto

 

        log_msg = f”IP Packet: {ip_src} -> {ip_dst} | Protocol: {protocol}”

 

        if packet.haslayer(“TCP”):

            tcp_sport = packet[“TCP”].sport

            tcp_dport = packet[“TCP”].dport

            log_msg += f” | TCP Ports: {tcp_sport} -> {tcp_dport}”

 

            if packet.haslayer(“Raw”):

                payload = packet[“Raw”].load.decode(errors=’ignore’)

                If payload.startswith(“GET”):

                    log_msg += ” | HTTP GET request detected”

 

        logger.info(log_msg)

        print(log_msg)

 

def process_packets():

    while True:

        Try:

            packet = packet_queue.get(timeout=3)

        Except queue.Empty:

            continue

        analyze_and_log(packet)

        packet_queue.task_done()

 

def save_packets(filename=”captured_packets.pcap”):

    wrpcap(filename, captured_packets)

    print(f”Saved {len(captured_packets)} packets to {filename}”)

 

def signal_handler(sig, frame):

    print(“Interrupt received, shutting down…”)

    packet_queue.join()

    save_packets()

    sys.exit(0)

 

def sniff_packets(interface=None, filter=None, count=0):

    sniff(iface=interface, filter=filter, prn=packet_handler, count=count)

 

if __name__ == “__main__”:

    signal.signal(signal.SIGINT, signal_handler)

 

    interface = “eth0”

    bpf_filter = “tcp port 80”

 

    processor_thread = threading.Thread(target=process_packets)

    processor_thread.daemon = True

    processor_thread.start()

 

    print(f”Starting packet capture on {interface} with filter ‘{bpf_filter}'”)

    sniff_packets(interface=interface, filter=bpf_filter)

 

This final part completes a robust thread-based network sniffer in Python using Scapy, equipped with:

  • Layered packet filtering combining BPF and custom logic

  • Advanced packet content inspection for application-layer data

  • Asynchronous logging for efficient record keeping

  • Safe multithreaded design with queues

  • Packet export for offline review and sharing

  • Graceful shutdown to avoid data loss

By building upon these foundations, you can customize the sniffer to your specific use cases such as intrusion detection, traffic analysis, or network troubleshooting.

If you want to extend further, consider adding GUI controls, integrating alerting systems, or performing machine learning-based anomaly detection on the captured traffic.

Final Thoughts

Building a thread-based network sniffer in Python with Scapy opens up powerful possibilities for capturing and analyzing network traffic in real time. Throughout this series, you’ve seen how threading helps handle packet processing efficiently without losing data, especially when dealing with high-speed networks or complex traffic patterns.

By combining built-in Berkeley Packet Filter expressions with custom in-code filtering, you can precisely target the packets that matter most to your analysis. This layered filtering approach optimizes performance and focuses on relevant traffic without overwhelming your system.

The ability to inspect packets beyond basic headers, such as detecting HTTP requests or analyzing payload contents, elevates your sniffer from a passive listener to an active network observer. Incorporating asynchronous logging preserves system responsiveness while maintaining comprehensive records for auditing or troubleshooting.

Exporting captured packets to standard PCAP files ensures your data can be reviewed or shared with other tools like Wireshark, facilitating deeper offline analysis and collaboration. Additionally, building graceful shutdown handling protects against data loss and guarantees clean resource management.

While this series covered a solid foundation, the realm of network sniffing offers many more advanced avenues. You could integrate real-time alerting, visualization dashboards, protocol-specific dissectors, or even machine learning models to detect anomalies and intrusions automatically.

Mastering thread-based sniffing with Scapy is a valuable skillset for network administrators, security professionals, and developers alike. It equips you with hands-on control over your network monitoring efforts, enabling tailored solutions to complex networking challenges.

I encourage you to experiment further, customize the examples, and build tools that fit your unique needs. With Python’s flexibility and Scapy’s powerful packet manipulation capabilities, the possibilities for network analysis and security are vast.

If you ever want to explore specific features or expand your sniffer into a comprehensive monitoring system, feel free to reach out. Happy sniffing!

 

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