For home, it can be usefull to get your external ip to get your services from internet to your home network, evrey time ip change, will send a email to previous configuration

registerIp.py

#Auth
#python3.4 or newer
#use "screen python3 registerIp.py" for better experience then ctrl+a+d and 'screen -r' (see more screen linux command on google)
#to stop ctrl + c
#interesting url to develope this
#help from https://medium.com/greedygame-engineering/an-elegant-way-to-run-periodic-tasks-in-python-61b7c477b679 (but in python 2)
#if you want to mount your own server https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-postfix-as-a-send-only-smtp-server-on-ubuntu-16-04
#https://www.freecodecamp.org/news/send-emails-using-code-4fcea9df63f/
#
#This script is designed for who wants the external ip and send it with email. For who want to have services at home
#or anywhere with dynamic external ip without paying for dynamic dns
#Need a external URL that return only your ip
#Tested with python 3.7 in ubuntu 18.04 using outlook account aka @hotmail.com
#
import urllib.request, threading, getpass, time, signal, datetime, smtplib
from datetime import timedelta

from string import Template

from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

__author__ = "guim1111"

#URL which will tell you only the ip
URL_GETIP = "https://ident.me"
#Time that wait to get again the ip from url in seconds
WAIT_TIME_SECONDS = 5
#do not touch
LAST_IP = "0"
#Edit this if you want to hardcode this (password not recommended)
MY_ADDRESS = ""
TO_ADDRESS = ""
MY_PASSWORD = ""
#Edit this for smtp that you want, but recommended this default, (only ports that accept ssl)
SMTP_HOST = "smtp-mail.outlook.com" #default for outlook account, gmail need more steps to be used with smtplib
SMTP_PORT = "587" #try 25 if doesn't work, ssl smpt port recommended

class ProgramKilled(Exception):
	pass

def getIp():
    global LAST_IP
    ip = urllib.request.urlopen(URL_GETIP).read().decode('utf8')
    now=datetime.datetime.now()
    if LAST_IP != ip:
        sendMail(ip)
        LAST_IP = ip
        file.write("{} -- {}\n".format(ip, now))
    print(f"{ip} detectada! -- {now}")

def signalHandler(signum, frame):
    raise ProgramKilled

def sendMail(ip):
    s = smtplib.SMTP(host=SMTP_HOST, port=SMTP_PORT)
    s.starttls()
    s.login(MY_ADDRESS, MY_PASSWORD)
    msg = MIMEMultipart()
    msg["From"]=MY_ADDRESS
    msg["To"]=TO_ADDRESS
    msg["Subject"]=f"Your ip now is: {ip}"
    msg.attach(MIMEText(f"Your ip was {LAST_IP}, now it's {ip}", "plain"))
    s.send_message(msg)
    del msg
    s.quit()

class Job(threading.Thread):
    def __init__(self, interval, execute, *args, **kwargs):
        threading.Thread.__init__(self)
        self.daemon = False
        self.stopped = threading.Event()
        self.interval = interval
        self.execute = execute
        self.args = args
        self.kwargs = kwargs

    def stop(self):
        self.stopped.set()
        self.join()
    def run(self):
        while not self.stopped.wait(self.interval.total_seconds()):
            self.execute(*self.args, **self.kwargs)

def checkSMTPCredentials():
    global MY_ADDRESS
    global TO_ADDRESS
    global MY_PASSWORD
    if MY_ADDRESS == "":
        MY_ADDRESS = input("Set a mail from where this script will work: ")
        TO_ADDRESS = input("Set a mail which will receive the mails (blank = previous email): ") or MY_ADDRESS
    else:
        print("There is a mail hardcoded, be sure you put it correct and the mail who will receive")
    if MY_PASSWORD == "":
        MY_PASSWORD = getpass.getpass("Set a password of first mail account (this will not be stored in any file): ")
    else:
        print("There is a password hardcoded (BE SURE THAT THIS IS WHAT YOU WANT, it's unsecure to put a credentials in any file)")
        if input("Write 'ok' to continue with this") != "ok":
            exit(1)
    print(f"Checking credentials for {SMTP_HOST}")
    s = smtplib.SMTP(host=SMTP_HOST, port=SMTP_PORT)
    s.starttls()
    try:
        s.login(MY_ADDRESS, MY_PASSWORD)
    except smtplib.SMTPAuthenticationError:
        print ("Incorrect username/password for this SMTP!")
        s.quit()
        exit(1)
    s.quit()
    print("Credentials are correct!")

def checkIp():
    response = urllib.request.urlopen(URL_GETIP)
    ip = response.read().decode('utf8')
    code = response.getcode()
    if code != 200:
        print("Something is wrong, the code of conectio is not 200")
        exit(2)
    print(f"Statuss 200, your ip is {ip} get from {URL_GETIP}")

def main():
    file=open("myip.log", "w+")
    signal.signal(signal.SIGTERM, signalHandler)
    signal.signal(signal.SIGINT, signalHandler)
    job = Job(interval=timedelta(seconds=WAIT_TIME_SECONDS), execute=getIp)
    job.start()

    while True:
        try:
            time.sleep(1)
        except ProgramKilled:
            print ("Program killed, bye!")
            job.stop()
            file.close()
            break

if __name__ == "__main__":
#Coment checkSMTPCredentials if you want to automate all without user input with hardcoded credentials (not secure)
#Coment checkIp if you don't want to check if web that tell your ip is up or you have internet connectivity
    checkSMTPCredentials()
    checkIp()
    main()