Client.py

from time import sleep
import keyboard
import socket

s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
down = False


def onKeyboardDownEvent():
    global down
    if not down:
        message = "down".encode("ascii")
        s.sendto(message, remote)
        down = True


def onKeyboardUpEvent():
    global down
    if down:
        message = "up".encode("ascii")
        s.sendto(message, remote)
        down = False


remote = (socket.gethostbyname("keridos"), 12455)
keyboard.hook_key('f13', onKeyboardDownEvent, onKeyboardUpEvent)

try:
    while True:
        sleep(1)
finally:
    print("error or quit")
    keyboard.unhook_all()

Server.py

import pyautogui
import socket

s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
host = socket.gethostname()
port = 12455
s.bind((host, port))

try:
    while True:
        msg, addr = s.recvfrom(1024)
        if msg.decode("ascii") == "down":
            pyautogui.keyDown('scrolllock')
            print("down")
        elif msg.decode("ascii") == "up":
            pyautogui.keyUp('scrolllock')
            print("up")

finally:
    s.shutdown(2)
    s.close()