Python network programming cheat sheet

All the tables provided in the cheat sheets are also presented in tables below which are easy to copy and paste.

The Python Network Programming Cheat Sheet covers:

  • Required common installation modules: PIP and IDLE
  • Top python network programming libraries
  • Network forensics: Required python libraries and scripts
  • Python Keywords
  • Data Types, Math operators
  • Network Analysis with Python
  • The dnspython library
  • Socket Module (Berkley API interface)
  • Socket Types, Creating Sockets
  • Socket Examples
  • Script Examples
  • Parsing Modules

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Python Cheat Sheet

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What’s included in this cheat sheet

The following categories and items have been included in the cheat sheet:

Required common installation modules: PIP and IDLE

PIP (Python Package Installer)

$ sudo apt-get install python-pip

IDLE (Integrated Development and Learning Environment)

$ sudo apt-get install idle

Top python network programming libraries


High-level Python Web framework for rapid development and pragmatic

pycos (formerly asyncoro)

Python framework for asynchronous, concurrent, network, distributed programming and distributed computing


A clean API for writing network clients and servers. TCP and UDP supported. Bundles clients for HTTP, DNS, Redis, Riak and MongoDB.


Easy way to build scalable network programs


Event-based framework for internet applications: HTTP clients and servers, SSHv2 and Telnet, IRC, XMPP, IMAPv4, POP3, SMTP, IMAPv4, POP3, SMTP, etc.


Network Automation and Programmability Abstraction Layer with Multivendor support - For dealing with dvice vendors


A coroutine -based Python networking library that uses greenlet to provide a high-level synchronous API on top of the libev or libuv event loop


Asynchronous task queue/job queue based on distributed message passing

Network forensics: Required python libraries and scripts


System and network monitoring, security, and performance analysis agent for python


Small packet capture tool based on python and pcap


Implementation of the SSHv2 protocol, providing both client and server functionality


Package installer for python

The Python Package Index (PyPI)

Repository of software for the Python

Python Keywords

>>> import keyword
>>> print(keyword.kwlist)

Python 2.7.15+ ['and', 'as', 'assert', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else', 'except', 'exec', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'not', 'or', 'pass', 'print', 'raise', 'return', 'try', 'while', 'with', 'yield']

Python 3.8.0 ['False', 'None', 'True', 'and', 'as', 'assert', 'async', 'await', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else', 'except', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'nonlocal', 'not', 'or', 'pass', 'raise', 'return', 'try', 'while', 'with', 'yield']

Data Types


str - x = "Hello World"


int, float, complex


list, tuple, range




set, frozenset




bytes, bytearray, memoryview

Math operators


Exponent 4 ** 2 = 16


Modulus/Remainder 43 % 5 = 3


Integer division 11 // 5 = 2


Division 11 / 5 = 2.2


Multiplication 3 * 3 = 9


Subtraction 8 - 3 = 5


Addition 2 + 2 = 4


Equal to


Not equal to


Less than


Greater Than


Less than or Equal to


Greater than or Equal to



Can be used at the start of a line, or from within a line to the end of the line

Network Analysis with Python

Use NMAP with port scanner

$ pip install python-nmap

Commands to run NMAP scan

import nmap
nmScan = nmap.PortScanner()
nmScan.scan('', '25-443')

NMAP commands used with python

nmScan.scaninfo() # {'tcp': {'services': ‘25-80’, 'method': 'connect'}}
nmScan['']['tcp'].keys() # Results -[80, 25, 22, 135]
nmScan[''].has_tcp(25) # Result True/False
nmScan[''].has_tcp(21) # Result False/True

The dnspython library


$ pip install dnspython

Basic DNS query

import dns.resolver
name = ''
for qtype in 'A', 'AAAA', 'MX', 'NS', 'TXT', 'SOA':
answer = dns.resolver.query(name,qtype, raise_on_no_answer=False)
if answer.rrset is not None:

Get MX target and name preference

import dns.resolver

answers = dns.resolver.query('', 'MX')
for rdata in answers:
print ('Host',, 'has preference', rdata.preference)

Socket Module (Berkley API interface)

Primary Functions an Methods

socket() • ind() • listen() • accept() • connect() • connect_ex() • send() • recv() • close()

Socket Types


For TCP protocols • Reliable transmission • Packet sequence • Connection-oriented • Bidirectional


For UDP protocols • Unreliable transmission • No sequence of packets • Connectionless(UDP) • Not Bidirectional

Creating Sockets

import socket # Imports the socket method

socket.socket() # Function that creates socket

sock = socket. socket (socket family, socket type, protocol=value)

Socket Family


Socket Type

SOCK_STREAM or SOCK_DGRAM for TCP & UDP respectively

• e.g. TCP - UDP2 = socket. socket (socket.AF_INET, socket.SOCK_DGRAM)

• e.g. UDP - TCP2 = socket. socket (socket.AF_INET, socket.SOCK_STREAM)

Client socket method


Server socket method

bind() • listen(backlog) • accept()

TCP socket methods

s.recv() # Receive TCP packets
s.send() #Send TCP packets

UDP socket methods

s.recvfrom() # Receives UDP packets
s.sendto() # Transmits UDP packets

More Socket Methods


Close the socket connection


Returns a string which includes the hostname of the current PC


Returns a string which includes the hostname and IP address of the current PC


Setup and start TCP listener


Attach (host-name, port number) to the socket


TCP client connection wait


Initiate TCP server connection

TCP Socket Methods


Returns a tuple with the remote address that has connected

mysocket.bind( address )

Attach the specified local address to the socket

mysocket.connect( address )

Data sent through the socket assigns to the given remote address


Returns the remote address where the socket is connected


Returns the address of the socket’s own local endpoint

mysocket.sendto(data, address)

Force a data packet to a specific remote address

Socket Blocking


Setup block


Remove / un-setup block

Get port number using domain name

import socket
socket.getservbyname('domain name')

Check support for IPV6

import socket
socket.has_ipv6 # Answer is TRUE or FALSE

getaddrinfo() - Bind Server to a Port

from socket import getaddrinfo
getaddrinfo(None, 'FTP', 0, socket.SOCK_STREAM, 0, socket.AI_PASSIVE)
[(2, 1, 6, '', ('', 21)), (10, 1, 6, '', ('::', 21, 0, 0))]

Socket Examples

Client-side socket example

import socket
myserver.bind((host,port)) # replace myserver and myclient with repsctive IPs
while True:
print("Connected to {str(addr)}")

Client-side Socket example with Comments

# import the socket library
import socket

# create a socket object
s = socket.socket()
print ("Socket created")

# reserve a port on the computer which can be anything
port = 1111

# bind to the port
# empty string in the IP field instead of an IP makes server listen to requests
# coming from other computers on the network
s.bind(('', port))
print ("socket binded to %s" %(port))

# make socket into listening mode
print ("socket is listening")

# loop until user interrupt it or an error occurs
while True:

# Establish connection with client.
c, addr = s.accept()
print ('Got connection from', addr)

# send a thank you message to the client.
c.send('Thank you for connection')

# Close the connection

Script Examples

Create list of devices

>>>devices = ['SW1', 'SW2', 'SW3']

Create VLAN dictionary list

vlans = [{'id': '100', 'name': 'staff'}, {'id': '200', 'name': 'VOICE'},
{'id': '300', 'name': 'wireless'}]

Write functions to collect commands and push to the network

>>>def get_commands(vlan, name):
commands = []
commands.append('vlan ' + vlan)
commands.append('name ' + name)

return commands

>>> def push_commands(device, commands):
print('Connecting to device: ' + device)
for cmd in commands:
print('Sending command: ' + cmd)

Create VLANs in multiple switches using python script

>>>for vlan in vlans:
id = vlan.get('id')
name = vlan.get('name')
print('Configure VLAN:' + id)
commands = get_commands(id, name)
for device in devices:
push_commands(device, commands)


Disable router interface using python command

>>> from push import push_commands
device = 'router2'
commands = ['interface Eth0/1', 'shutdown']
push_commands(device, commands)

Parsing Modules


The argparse module makes it easy to write user-friendly command-line interfaces. The program defines what arguments it requires, and argparse will figure out how to parse those out of sys.argv

Creating a parser

>>> parser = argparse.ArgumentParser(description='Process some integers.')

Adding arguments

>>> parser.add_argument('integers', metavar='N', type=int, nargs='+',
... help='an integer for the accumulator')
>>> parser.add_argument('--sum', dest='accumulate', action='store_const',
... const=sum, default=max,
... help='sum the integers (default: find the max)')

Parsing arguments

>>> parser.parse_args(['--sum', '7', '-1', '42'])
Namespace(accumulate=, integers=[7, -1, 42])

Python network programming FAQs

How Python can be used in networking?

Python is a flexible programming language and it can be used to automate many business tasks. On networks, you would use Python scripts to perform maintenance tasks, collect and transform data, or to update settings. A useful application for Python on networks is to ensure coordination between different components in a system. For example, all of the elements in a software-defined network can be aligned through the use of Python scripts.

Is Python good for socket programming?

You can bind and release a socket with Python very easily. There are a number of network traffic management services that you can construct with Python, such as resequencing packets or checking for abandoned connections.

Why is Python good for network automation?

The short answer to why Python is good for network programming is that Cisco System uses it for the on-board programs on its devices, so if they put in lots of research into the relative benefits of programming languages for networking, you could just take their word for it and save yourself a lot of time. Pointing to the qualities that recommend Python for network programming is that it is extensible by libraries in the way that C is but it is much easier to read than C and it doesn’t need to be compiled.