This short slides demonstrating how to create simple UDP broadcast app using Python Socket on WIndows & Linux. There are some important notes, especially when writing Python script on different OS/kernel (On Windows, you need to bind network interface IP, while on Linux you should use SO_REUSEPORT, unless you're using kernel <3.9..change to SO_REUSEADDR)

1. Creating UDP Broadcast App
Using Python Socket
on Windows & Linux
Dony Riyanto
June 2021
Telegram: @donyriyanto
slideshare.net/donyriyanto

3. Receiver.py

4. Notes:
• SO_REUSEPORT enable port reusage so we will be able to run
multiple clients and servers on single (host, port). Do not use
socket.SO_REUSEADDR except you using linux(kernel<3.9): goto
https://stackoverflow.com/questions/14388706/how-do-so-
reuseaddr-and-so-reuseport-differ for more information.
• For linux hosts all sockets that want to share the same address and
port combination must belong to processes that share the same
effective user ID! So, on linux(kernel>=3.9) you have to run multiple
servers and clients under one user to share the same (host, port).
Thanks to @stevenreddie
• For Windows OS, it is important to bind it to network interface IP.

5. Sender.py
Important for Windows OS

6. Testing
Local Laptop
Windows 7
192.168.1.19
PC
Windows 7
192.168.1.12
VM in PC
Ubuntu 18
192.168.1.11
(bridge)
Local Area Network
Succesfully on the same host

7. Testing
Local Laptop
Windows 7
192.168.1.19
PC
Windows 7
192.168.1.12
VM in PC
Ubuntu 18
192.168.1.11
(bridge)
Local Area Network
Succesfully on the different host, same OS version, LAN over WiFi

8. Testing
Local Laptop
Windows 7
192.168.1.19
PC
Windows 7
192.168.1.12
VM in PC
Ubuntu 18
192.168.1.11
(bridge)
Local Area Network
Succesfully on the different host, different OS, accros bridge network driver, LAN over WiFi