Book Image

Python Network Programming

By : Abhishek Ratan, Eric Chou, Pradeeban Kathiravelu, Dr. M. O. Faruque Sarker
Book Image

Python Network Programming

By: Abhishek Ratan, Eric Chou, Pradeeban Kathiravelu, Dr. M. O. Faruque Sarker

Overview of this book

This Learning Path highlights major aspects of Python network programming such as writing simple networking clients, creating and deploying SDN and NFV systems, and extending your network with Mininet. You’ll also learn how to automate legacy and the latest network devices. As you progress through the chapters, you’ll use Python for DevOps and open source tools to test, secure, and analyze your network. Toward the end, you'll develop client-side applications, such as web API clients, email clients, SSH, and FTP, using socket programming. By the end of this Learning Path, you will have learned how to analyze a network's security vulnerabilities using advanced network packet capture and analysis techniques. This Learning Path includes content from the following Packt products: • Practical Network Automation by Abhishek Ratan • Mastering Python Networking by Eric Chou • Python Network Programming Cookbook, Second Edition by Pradeeban Kathiravelu, Dr. M. O. Faruque Sarker

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Python Network Programming
Abhishek Ratan | Eric Chou | Pradeeban Kathiravelu | Dr. M. O. Faruque Sarker
Jan, 2019 | 12 hours 56 minutes
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Table of Contents (30 chapters)
Title Page
Title Page
Copyright
Copyright
About Packt
About Packt
Contributors
Contributors
Preface
Preface
Free Chapter
1
Fundamental Concepts
Fundamental Concepts
Network automation
DevOps
Software-defined networking
OpenFlow
Program concepts
Language choices (Python/PowerShell)
Representational State Transfer (REST) framework
Summary
2
Python for Network Engineers
Python for Network Engineers
Python interpreter and data types
Conditions and loops
Writing Python scripts
Functions
Python modules and packages
Multithreading for parallel processing
Using Netmiko for SSH and network device interaction
Network automation use case
Summary
3
Continuous Integration for Network Engineers
Continuous Integration for Network Engineers
Interaction with Splunk
Automation examples on various technology domains
Example and use case
Summary
4
SDN Concepts in Network Automation
SDN Concepts in Network Automation
Managing cloud platforms
Programmable network devices
Controller-based network fabric
Network automation tools
Summary
5
Low-Level Network Device Interactions
Low-Level Network Device Interactions
The challenges of the CLI
Constructing a virtual lab
Python Pexpect library
The Python Paramiko library
Looking ahead
Summary
6
APIs and Intent-Driven Networking
APIs and Intent-Driven Networking
Infrastructure as code
The Cisco API and ACI
The Python API for Juniper networks
The Arista Python API
Vendor-neutral libraries
Summary
7
The Python Automation Framework – Ansible Basics
The Python Automation Framework – Ansible Basics
A more declarative framework
A quick Ansible example
The advantages of Ansible
The Ansible architecture
Ansible networking modules
The Ansible Cisco example
The Ansible Juniper example
The Ansible Arista example
Summary
8
The Python Automation Framework – Beyond Basics
The Python Automation Framework – Beyond Basics
Ansible conditionals
Ansible loops
Templates
Group and host variables
The Ansible Vault
The Ansible include and roles
Writing your own custom module
Summary
9
AWS Cloud Networking
AWS Cloud Networking
AWS setup
AWS network overview
Virtual private cloud
Direct Connect and VPN
Network scaling services
Other AWS network services
Summary
10
Working with Git
Working with Git
Introduction to Git
Setting up Git
Git usage examples
Git with Python
Automating configuration backup
Collaborating with Git
Summary
11
Sockets, IPv4, and Simple Client/Server Programming
Sockets, IPv4, and Simple Client/Server Programming
Introduction
Printing your machine's name and IPv4 address
Retrieving a remote machine's IP address
Converting an IPv4 address to different formats
Finding a service name, given the port and protocol
Converting integers to and from host to network byte order
Setting and getting the default socket timeout
Handling socket errors gracefully
Modifying a socket's send/receive buffer sizes
Changing a socket to the blocking/non-blocking mode
Reusing socket addresses
Printing the current time from the internet time server
Writing an SNTP client
Writing a simple TCP echo client/server application
Writing a simple UDP echo client/server application
12
Multiplexing Socket I/O for Better Performance
Multiplexing Socket I/O for Better Performance
Introduction
Using ForkingMixIn in your socket server applications
Using ThreadingMixIn in your socket server applications
Writing a chat server using select.select
Multiplexing a web server using select.epoll
Multiplexing an echo server using Diesel concurrent library
13
IPv6, Unix Domain Sockets, and Network Interfaces
IPv6, Unix Domain Sockets, and Network Interfaces
Introduction
Forwarding a local port to a remote host
Pinging hosts on the network with ICMP
Waiting for a remote network service
Enumerating interfaces on your machine
Finding the IP address for a specific interface on your machine
Finding whether an interface is up on your machine
Detecting inactive machines on your network
Performing a basic IPC using connected sockets (socketpair)
Performing IPC using Unix domain sockets
Finding out if your Python supports IPv6 sockets
Extracting an IPv6 prefix from an IPv6 address
Writing an IPv6 echo client/server
14
Programming with HTTP for the Internet
Programming with HTTP for the Internet
Introduction
Downloading data from an HTTP server
Serving HTTP requests from your machine
Extracting cookie information after visiting a website
Submitting web forms
Sending web requests through a proxy server
Checking whether a web page exists with the HEAD request
Spoofing Mozilla Firefox in your client code
Saving bandwidth in web requests with the HTTP compression
Writing an HTTP fail-over client with resume and partial downloading
Writing a simple HTTPS server code with Python and OpenSSL
Building asynchronous network applications with Twisted
Building asynchronous network applications with Tornado
Building concurrent applications with Tornado Future
15
Email Protocols, FTP, and CGI Programming
Email Protocols, FTP, and CGI Programming
Introduction
Listing the files in a remote FTP server
Uploading a local file to a remote FTP server
Emailing your current working directory as a compressed ZIP file
Downloading your Google email with POP3
Checking your remote email with IMAP
Sending an email with an attachment via Gmail SMTP server
Writing a guestbook for your (Python-based) web server with CGI
Finding the mail server from an email address
Writing a simple SMTP server
Writing a secure SMTP client using TLS
Writing an email client with POP3
16
Programming Across Machine Boundaries
Programming Across Machine Boundaries
Introduction
Executing a remote shell command using telnet
Copying a file to a remote machine by SFTP
Printing a remote machine's CPU information
Installing a Python package remotely
Running a MySQL command remotely
Transferring files to a remote machine over SSH
Configuring Apache remotely to host a website
17
Working with Web Services – SOAP, and REST
Working with Web Services – SOAP, and REST
Introduction
Querying a local XML-RPC server
Writing a multithreaded, multicall XML-RPC server
Running an XML-RPC server with a basic HTTP authentication
Collecting some photo information from Flickr using REST
Searching for SOAP methods from an Amazon S3 web service
Searching Amazon for books through the product search API
Creating RESTful web applications with Flask
18
Network Monitoring and Security
Network Monitoring and Security
Introduction
Sniffing packets on your network
Saving packets in the pcap format using the pcap dumper
Adding an extra header in HTTP packets
Scanning the ports of a remote host
Customizing the IP address of a packet
Replaying traffic by reading from a saved pcap file
Scanning the broadcast of packets
19
Network Modeling
Network Modeling
Introduction
Simulating networks with ns-3
Emulating networks with Mininet
Distributed network emulation with MaxiNet
Emulating wireless networks with Mininet-WiFi
Extending Mininet to emulate containers
20
Authentication, Authorization, and Accounting (AAA)
Authentication, Authorization, and Accounting (AAA)
Introduction
Finding DNS names of a network
Finding DNS host information
Finding DNS resource records
Making DNS zone transfer
Querying NTP servers
Connecting to an LDAP server
Making LDAP bind
Reading and writing LDAP
Authenticating REST APIs with Eve
Throttling requests with RequestsThrottler
21
Open and Proprietary Networking Solutions
Open and Proprietary Networking Solutions
Introduction
Configuring Red PNDA
Configuring VMware NSX for vSphere 6.3.2
Configuring Juniper Contrail Server Manager
Configuring OpenContrail controller
Configuring OpenContrail cluster
Interacting with devices running Cisco IOS XR
Collaborating with Cisco Spark API
22
NFV and Orchestration – A Larger Ecosystem
NFV and Orchestration – A Larger Ecosystem
Introduction
Building VNFs with OPNFV
Packet processing with DPDK
Parsing BMP messages with SNAS.io
Controlling drones with a wireless network
Creating PNDA clusters
23
Programming the Internet
Programming the Internet
Introduction
Checking a website status
Benchmarking BGP implementations with bgperf
BGP with ExaBGP
Looking glass implementations with Python
Understanding the internet ecosystem with Python
Establishing BGP connections with yabgp
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Index
Index

Downloading your Google email with POP3

You would like to download your Google (or virtually any other email provider's) email via the POP3 protocol.

Getting ready

To run this recipe, you should have an email account with Google or any other service provider.

How to do it...

Here, we attempt to download the first email message from a user's Google email account. The username is supplied from a command line, but the password is kept secret and not passed from the command line. This is rather entered while the script is running and kept hidden from display.

Listing 5.4 shows how to download our Google email via POP3 as follows:

#!/usr/bin/env python 
# Python Network Programming Cookbook, Second Edition -- Chapter - 5 
# This program is optimized for Python 2.7.12 and Python 3.5.2. 
# It may run on any other version with/without modifications. 
 
import argparse 
import getpass 
import poplib 
 
GOOGLE_POP3_SERVER = 'pop.googlemail.com' 
 
def download_email(username):  
    mailbox = poplib.POP3_SSL...
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